a(n) = Sum_{k=0..8} binomial(16,k)*binomial(n,k).

Terms

a(0) =1a(1) =17a(2) =153a(3) =969a(4) =4845a(5) =20349a(6) =74613a(7) =245157a(8) =735471a(9) =2031535a(10) =5189327a(11) =12316239a(12) =27322191a(13) =57029103a(14) =112740255a(15) =212383935a(16) =383358645a(17) =666220005a(18) =1119362365a(19) =1824861005a(20) =2895653673a(21) =4484253081a(22) =6793194849a(23) =10087438257a(24) =14708950035a(25) =21093714291