a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)*(3n^2 + 15n + 20)/2880.

Terms

a(0) =1a(1) =19a(2) =155a(3) =805a(4) =3136a(5) =9996a(6) =27468a(7) =67320a(8) =150645a(9) =313027a(10) =611611a(11) =1134497a(12) =2012920a(13) =3436720a(14) =5673648a(15) =9093096a(16) =14194881a(17) =21643755a(18) =32310355a(19) =47319349a(20) =68105576a(21) =96479020a(22) =134699500a(23) =185562000a(24) =252493605a(25) =339663051a(26) =452103939