100 Arranged probability -- v3.sf

#!/usr/bin/ruby

# Author: Trizen
# Date: 15 March 2023
# https://github.com/trizen

# https://projecteuler.net/problem=100

# Runtime: 0.268s

var n = bsearch_ge({|n|
    Math.linear_rec([7, -7, 1], [0, 3, 20], n) <=> 1e12
})

say Math.linear_rec([7, -7, 1], [1, 3, 15], n)