a(n) = n*(4*n^6 + 70*n^4 + 196*n^2 + 45)/315.

Terms

a(0) =0a(1) =1a(2) =14a(3) =99a(4) =476a(5) =1765a(6) =5418a(7) =14407a(8) =34232a(9) =74313a(10) =149830a(11) =284075a(12) =511380a(13) =880685a(14) =1459810a(15) =2340495a(16) =3644272a(17) =5529233a(18) =8197758a(19) =11905267a(20) =16970060a(21) =23784309a(22) =32826266a(23) =44673751a(24) =60018984a(25) =79684825a(26) =104642486a(27) =136030779a(28) =175176964a(29) =223619261