Safe primes and unsafe primes: Difference between revisions

{{works with|HP|49g}}

≪

1 - 2 /

'''IFERR''' ISPRIME? '''THEN''' DROP 0 '''END'''

≫ '<span style="color:blue">SAFE?</span>' STO

≪ → function count

≪ { } 2

'''WHILE''' OVER SIZE count < '''REPEAT '''

'''IF''' DUP function EVAL '''THEN''' SWAP OVER + SWAP '''END'''

NEXTPRIME

'''END'''

DROP

≫ ≫ '<span style="color:blue">FIRSTSEQ</span>' STO

≪ → function max

≪ 0 2

'''WHILE''' DUP max < '''REPEAT '''

'''IF''' DUP function EVAL '''THEN''' SWAP 1 + SWAP '''END'''

NEXTPRIME

'''END'''

DROP

≫ ≫ '<span style="color:blue">CNTSEQ</span>' STO

≪ <span style="color:blue">SAFE?</span> ≫ 35 <span style="color:blue">FIRSTSEQ</span>

≪ <span style="color:blue">SAFE?</span> ≫ 10000 <span style="color:blue">CNTSEQ</span>

≪ <span style="color:blue">SAFE?</span> NOT ≫ 40 <span style="color:blue">FIRSTSEQ</span>

≪ <span style="color:blue">SAFE?</span> NOT ≫ 10000 <span style="color:blue">CNTSEQ</span>

Counting safe numbers up to one million would take an hour, without really creating any opportunity to improve the algorithm or the code.

{{out}

<pre>

4: {5 7 11 23 47 59 83 107 167 179 227 263 347 359 383 467 479 503 563 587 719 839 863 887 983 1019 1187 1283 1307 1319 1367 1439 1487 1523 1619}

3: 115

2: {2 3 13 17 19 29 31 37 41 43 53 61 67 71 73 79 89 97 101 103 109 113 127 131 137 139 149 151 157 163 173 181 191 193 197 199 211 223 229 233}

1: 1114

</pre>