a(n) = binomial(2*n+1, n+1)*binomial(n+4, 4).

Terms

a(0) =1a(1) =15a(2) =150a(3) =1225a(4) =8820a(5) =58212a(6) =360360a(7) =2123550a(8) =12033450a(9) =66050270a(10) =353068716a(11) =1845586470a(12) =9464546000a(13) =47738754000a(14) =237329805600