pentathing.raku

#! /usr/bin/env -S raku --profile=pentathing-profile.html

use v6.*;

sub is-pentagon($c is raw) { (1+sqrt(1+24*$c))%%6 }

sub P($n is raw) { $n*(3*$n-1) div 2 }
my atomicint $bail = 0;
(^∞).hyper(:batch(64)).map( -> \b {
    last if $bail;
    for (1..^b) -> \s { 
        my \bp = P(b); 
        my \sp = P(s);
        if is-pentagon(bp + sp) && is-pentagon(bp - sp) {
            say [b, s];
            $bail⚛++;
            say now - BEGIN now;
            last;
        }
    }
});