108 Diophantine reciprocals I.sf

#!/usr/bin/ruby

# Daniel "Trizen" Șuteu
# Date: 15 May 2021
# https://github.com/trizen

# Diophantine reciprocals I
# https://projecteuler.net/problem=108

# See also:
#   https://oeis.org/A018892

# Runtime: 2.468s (previously: 3.913s)

var N = 1000

1..Inf -> first {|n|
    (sigma0(n*n) + 1) > 2*N
} -> say