a(n) = (4!)^3 * [z^4] hypergeom([], [1,1], z)^n.

Terms

a(0) =0a(1) =1a(2) =346a(3) =6219a(4) =36628a(5) =124405a(6) =316206a(7) =672511a(8) =1267624a(9) =2189673a(10) =3540610a(11) =5436211a(12) =8006076a(13) =11393629a(14) =15756118a(15) =21264615a(16) =28104016a(17) =36473041a(18) =46584234a(19) =58663963a(20) =72952420a(21) =89703621a(22) =109185406a(23) =131679439a(24) =157481208a(25) =186900025a(26) =220259026a(27) =257895171a(28) =300159244