Find squares n where n+1 is prime: Difference between revisions
Find squares n where n+1 is prime (view source)
Revision as of 14:46, 18 December 2021
, 2 years ago→{{header|Perl}}: alternate solutions
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=={{header|Perl}}==
===Simple and Clear===
<lang perl>#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Find_squares_n_where_n%2B1_is_prime
use warnings;
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1 4 16 36 100 196 256 400 576 676
</pre>
===More Than One Way===
TMTOWTDI, right? So do it.
<lang perl>use strict;
use warnings;
use feature 'say';
use ntheory 'is_prime';
my $a; is_prime $_ and $a = sqrt $_-1 and $a == int $a and say $_-1 for 1..1000; # backwards approach
my $b; do { say $b**2 if is_prime 1 + ++$b**2 } until $b > int sqrt 1000; # do/until
my $c; while (++$c < int sqrt 1000) { say $c**2 if is_prime 1 + $c**2 } # while/if
say for map $_**2, grep is_prime 1 + $_**2, 1 .. int sqrt 1000; # for/map/grep
for (1 .. int sqrt 1000) { say $_**2 if is_prime 1 + $_**2 } # for/if
say $_**2 for grep is_prime 1 + $_**2, 1 .. int sqrt 1000; # for/grep
is_prime 1 + $_**2 and say $_**2 for 1 .. int sqrt 1000; # and/for
is_prime 1+$_**2&&say$_**2for 1..31; # and/for golf, FTW
# or dispense with the module and find primes the slowest way possible
(1 x (1+$_**2)) !~ /^(11+)\1+$/ and say $_**2 for 1 .. int sqrt 1000;</lang>
{{out}}
In all cases:
<pre>1
4
16
36
100
196
256
400
576
676</pre>
=={{header|Phix}}==
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