G.f. is the polynomial (Product_{k=1..14} (1 - x^(3*k)))/(1-x)^14.

Terms

a(0) =1a(1) =14a(2) =105a(3) =559a(4) =2366a(5) =8463a(6) =26571a(7) =75126a(8) =194817a(9) =469728a(10) =1064166a(11) =2284086a(12) =4675748a(13) =9179014a(14) =17358666a(15) =31744441a(16) =56319263a(17) =97205511a(18) =163611175a(19) =269111465a(20) =433356858a(21) =684315658a(22) =1061177819a(23) =1618066905a(24) =2428728445