project-euler/Sidef/293 Pseudo-Fortunate Numbers.sf

#!/usr/bin/ruby

# Daniel "Trizen" Șuteu
# License: GPLv3
# Date: 06 May 2017
# https://github.com/trizen

# https://projecteuler.net/problem=293

# Runtime: 0.671s (previously: 1.186s)

var limit = 1e9
var admis = []

func rec(n, p) {
    if (n>1 && n<limit) {
        admis << n
    }

    if (n*p < limit) {
        rec(n*p, p)
        rec(n*p, p.next_prime)
    }
}

rec(1, 2)

say admis.map {|n| (n+1).next_prime - n }.uniq.sum