Least m such that n! + m is prime: Difference between revisions
→{{header|Phix}}
(J draft (skipping stretch to avoid tediously tying up laptop while it crunches)) |
|||
Line 148:
First m > 12000 is 12619 at position 599.
</pre>
=={{header|Phix}}==
{{trans|C}}
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #7060A8;">requires</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1.0.3"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- mpz_nextprime() added </span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">LIMIT</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">10000</span>
<span style="color: #008080;">include</span> <span style="color: #004080;">mpfr</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #004080;">mpz</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">fact</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">mpz_inits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">diffs</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">t</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1000</span>
<span style="color: #008080;">while</span> <span style="color: #000000;">t</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">LIMIT</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">></span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #7060A8;">mpz_mul_si</span><span style="color: #0000FF;">(</span><span style="color: #000000;">fact</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fact</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">mpz_nextprime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fact</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">mpz_sub</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fact</span><span style="color: #0000FF;">);</span>
<span style="color: #000000;">m</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">mpz_get_integer</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">);</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">diffs</span><span style="color: #0000FF;">)<</span><span style="color: #000000;">50</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">diffs</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">m</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">diffs</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">50</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"Least positive m such that n! + m is prime; first 50:\n%s\n"</span><span style="color: #0000FF;">,</span>
<span style="color: #0000FF;">{</span><span style="color: #7060A8;">join_by</span><span style="color: #0000FF;">(</span><span style="color: #000000;">diffs</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" "</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fmt</span><span style="color: #0000FF;">:=</span><span style="color: #008000;">"%3d"</span><span style="color: #0000FF;">)})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">elsif</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">></span><span style="color: #000000;">t</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">do</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"First m > %,6d is %,6d at position %,d\n"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">t</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">m</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">})</span>
<span style="color: #000000;">t</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1000</span>
<span style="color: #008080;">until</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">></span><span style="color: #000000;">m</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
Least positive m such that n! + m is prime; first 50:
1 1 1 1 5 7 7 11 23 17
11 1 29 67 19 43 23 31 37 89
29 31 31 97 131 41 59 1 67 223
107 127 79 37 97 61 131 1 43 97
53 1 97 71 47 239 101 233 53 83
First m > 1,000 is 1,069 at position 107
First m > 2,000 is 3,391 at position 192
First m > 3,000 is 3,391 at position 192
First m > 4,000 is 4,943 at position 284
First m > 5,000 is 5,233 at position 384
First m > 6,000 is 6,131 at position 388
</pre>
Note this is very slow, and still running.....
=={{header|Raku}}==
| |||