a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)*(3*n+5)/720.

Terms

a(0) =1a(1) =16a(2) =110a(3) =490a(4) =1666a(5) =4704a(6) =11592a(7) =25740a(8) =52635a(9) =100672a(10) =182182a(11) =314678a(12) =522340a(13) =837760a(14) =1303968a(15) =1976760a(16) =2927349a(17) =4245360a(18) =6042190a(19) =8454754a(20) =11649638a(21) =15827680a(22) =21229000a(23) =28138500a(24) =36891855a(25) =47882016a(26) =61566246a(27) =78473710