77995

Appears in sequences

• a(n) = n*(n + 1)*(13*n^2 + 13*n - 14)/24.at n=19A264888
• Square array T(n,k), n >= 1, k >= 1, read by antidiagonals, where T(n,k) is the number of ordered k-tuples (x_1, x_2, ..., x_k) with gcd(x_1, x_2, ..., x_k) = 1 (1 <= {x_1, x_2, ..., x_k} <= n).at n=59A344527