a(n) = (Product_{i=0..4}(i*n+2) - Product_{i=0..4}(-i*n-1))/(4*n+3).

Terms

a(0) =11a(1) =120a(2) =435a(3) =1064a(4) =2115a(5) =3696a(6) =5915a(7) =8880a(8) =12699a(9) =17480a(10) =23331a(11) =30360a(12) =38675a(13) =48384a(14) =59595a(15) =72416a(16) =86955a(17) =103320a(18) =121619a(19) =141960a(20) =164451a(21) =189200a(22) =216315a(23) =245904a(24) =278075a(25) =312936a(26) =350595a(27) =391160a(28) =434739a(29) =481440