a(n) = binomial(n+3, 3)/4 for odd n, n*(n+2)*(n+4)/24 for even n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =8a(5) =14a(6) =20a(7) =30a(8) =40a(9) =55a(10) =70a(11) =91a(12) =112a(13) =140a(14) =168a(15) =204a(16) =240a(17) =285a(18) =330a(19) =385a(20) =440a(21) =506a(22) =572a(23) =650a(24) =728a(25) =819a(26) =910a(27) =1015a(28) =1120a(29) =1240