from collections import defaultdict n = int(input()) a = list(map(int, input().split())) lim = 400010 ans = 0 cnt = defaultdict(int) for i in range(1, n + 1): for k in range(1, lim//i + 1): p = k*i-a[i-1] ans += cnt[(k << 20) + p] cnt[(k << 20) - p] += 1 print(ans)