a(n) = ((n + 1)/2)*(n + 2)*Pochhammer(n, 5) / 4!.

Terms

a(0) =0a(1) =15a(2) =180a(3) =1050a(4) =4200a(5) =13230a(6) =35280a(7) =83160a(8) =178200a(9) =353925a(10) =660660a(11) =1171170a(12) =1987440a(13) =3248700a(14) =5140800a(15) =7907040a(16) =11860560a(17) =17398395a(18) =25017300a(19) =35331450a(20) =49092120a(21) =67209450a(22) =90776400a(23) =121095000a(24) =159705000a(25) =208415025a(26) =269336340a(27) =344919330a(28) =437992800a(29) =551806200