Problem 443: GCD sequence
Let g(n) be a sequence defined as follows: g(4) = 13, g(n) = g(n-1) + gcd(n, g(n-1)) for n > 4.
The first few values are:
n 4567891011121314151617181920... g(n) 1314161718272829303132333451545560...
You are given that g(1 000) = 2524 and g(1 000 000) = 2624152.
Find g(1015).
Test
{{test}}Console output