import sys
input = sys.stdin.readline
mod = 998244353

N = int(input())
A = list(map(int, input().split()))

ans = 0
for i in range(N):
    prev = [0] * 2001
    X = [0] * 2001
    S = [0] * 2001
    B = [0] * N
    for j in range(i+1, N):
        if A[j] == A[i] + 10:
            B[j] = B[j - 1] + 1
        else:
            B[j] = B[j - 1]

        if A[j] > A[i] + 11:
            b = prev[A[j] - 1]
            prev[A[j] - 1] = B[j]
            S[A[j] - 1] += X[A[j] - 1] * (B[j] - b)
            ans += S[A[j] - 1]
            #S[A[j] - 1] = 0

        if A[j] > A[i] + 10:
            b = prev[A[j]]
            prev[A[j]] = B[j]
            S[A[j]] += X[A[j]] * (B[j] - b)
            X[A[j]] += 1
        #if i == 0:
        #    print(j, ans, X[:20], prev[:20])

print(ans)