project-euler/Sidef/231 The prime factorisation of binomial coefficients.sf

#!/usr/bin/ruby

# Author: Trizen
# Date: 25 August 2016
# Translated: 16 November 2023
# https://github.com/trizen

# https://projecteuler.net/problem=231

# Runtime: 22.889s

var n = 20000000
var k = 15000000
var j = n-k

var sum = 0

n.each_prime {|p|
    var e = factorial_valuation(n, p)

    if (p <= k) {
        e -= factorial_valuation(k, p)
    }

    if (p <= j) {
        e -= factorial_valuation(j, p)
    }

    sum += e*p
}

say sum