a(n) = Product_{i=1..n} ((i+3)*(i+4)*(i+5))/(i*(i+1)*(i+2)).

Terms

a(0) =1a(1) =20a(2) =175a(3) =980a(4) =4116a(5) =14112a(6) =41580a(7) =108900a(8) =259545a(9) =572572a(10) =1184183a(11) =2318680a(12) =4331600a(13) =7768320a(14) =13441968a(15) =22535064a(16) =36729945a(17) =58373700a(18) =90684055a(19) =138003404a(20) =206108980a(21) =302588000a(22) =437287500a(23) =622849500a(24) =875343105a(25) =1215006156a(26) =1667110095