130500domain: NAppears in sequencesa(n) = binomial(n+2,2) * binomial(n+7,2).at n=23A104676T(n, k) = [x^n] 2^n*P(n, x), where P(n, x) = (1 + 4*x)^(n + 1) + (1 - 2^(-2*n-1))*(2 + 4*x)^(n + 1). Triangle read by rows, T(n, k) for 0 <= k <= n+1 if n >= 0 and by convention T(-1, 0) = 0.at n=23A342317