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

Terms

a(0) =1a(1) =12a(2) =90a(3) =560a(4) =3150a(5) =16632a(6) =84084a(7) =411840a(8) =1969110a(9) =9237800a(10) =42678636a(11) =194699232a(12) =878850700a(13) =3931426800a(14) =17450721000a(15) =76938289920a(16) =337206098790