Primes whose first and last number is 3: Difference between revisions
Primes whose first and last number is 3 (view source)
Revision as of 02:40, 25 July 2021
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3343 3373 3413 3433 3463 3533 3583 3593 3613 3623 3643 3673
3733 3793 3803 3823 3833 3853 3863 3923 3943
</pre>
=={{header|Factor}}==
{{works with|Factor|0.99 2021-06-02}}
<lang factor>USING: formatting grouping io kernel lists lists.lazy math
math.functions math.primes sequences ;
: under ( list n -- list' ) '[ _ < ] lwhile ;
: (surrounded) ( n -- list )
[ 1list 1 lfrom ] keep dup dup
'[ 10^ _ * _ + [ [ 10 + ] lfrom-by ] keep dup _ / + 10 - under ]
lmap-lazy lconcat lappend-lazy ;
: surrounded ( n upto -- list )
[ (surrounded) ] [ under ] bi* [ prime? ] lfilter ;
: surrounded. ( n -- )
dup "Primes under 10,000 beginning and ending with %d:\n" printf
10,000 surrounded list>array 10 group
[ [ "%6d" printf ] each nl ] each nl ;
{ 1 3 5 7 9 } [ surrounded. ] each
3 1,000,000 surrounded llength
"Found %d primes beginning and ending with 3 under 1,000,000.\n" printf</lang>
{{out}}
<pre>
Primes under 10,000 beginning and ending with 1:
11 101 131 151 181 191 1021 1031 1051 1061
1091 1151 1171 1181 1201 1231 1291 1301 1321 1361
1381 1451 1471 1481 1511 1531 1571 1601 1621 1721
1741 1801 1811 1831 1861 1871 1901 1931 1951
Primes under 10,000 beginning and ending with 3:
3 313 353 373 383 3023 3083 3163 3203 3253
3313 3323 3343 3373 3413 3433 3463 3533 3583 3593
3613 3623 3643 3673 3733 3793 3803 3823 3833 3853
3863 3923 3943
Primes under 10,000 beginning and ending with 5:
5
Primes under 10,000 beginning and ending with 7:
7 727 757 787 797 7027 7057 7127 7177 7187
7207 7237 7247 7297 7307 7417 7457 7477 7487 7507
7517 7537 7547 7577 7607 7687 7717 7727 7757 7817
7867 7877 7907 7927 7937
Primes under 10,000 beginning and ending with 9:
919 929 9029 9049 9059 9109 9199 9209 9239 9319
9349 9419 9439 9479 9539 9619 9629 9649 9679 9689
9719 9739 9749 9769 9829 9839 9859 9929 9949
Found 2251 primes beginning and ending with 3 under 1,000,000.
</pre>
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