a(n) = (m(n)^2 + 3)*(m(n)^2 + 7)/32, where m(n) = 2*n - 1.

Terms

a(0) =1a(1) =6a(2) =28a(3) =91a(4) =231a(5) =496a(6) =946a(7) =1653a(8) =2701a(9) =4186a(10) =6216a(11) =8911a(12) =12403a(13) =16836a(14) =22366a(15) =29161a(16) =37401a(17) =47278a(18) =58996a(19) =72771a(20) =88831a(21) =107416a(22) =128778a(23) =153181a(24) =180901a(25) =212226a(26) =247456a(27) =286903a(28) =330891a(29) =379756