a(n) = binomial(n+7, 7) * binomial(n+9, 7).

Terms

a(0) =36a(1) =960a(2) =11880a(3) =95040a(4) =566280a(5) =2718144a(6) =11042460a(7) =39262080a(8) =125147880a(9) =364066560a(10) =979945824a(11) =2466996480a(12) =5859116640a(13) =13220570880a(14) =28506855960a(15) =59025960576a(16) =117846969900a(17) =227667211200a(18) =426876021000a(19) =778861512000