a(n) = n^4 - 10n^3 + 35n^2 - 48n + 23.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =33a(5) =131a(6) =373a(7) =855a(8) =1697a(9) =3043a(10) =5061a(11) =7943a(12) =11905a(13) =17187a(14) =24053a(15) =32791a(16) =43713a(17) =57155a(18) =73477a(19) =93063a(20) =116321a(21) =143683a(22) =175605a(23) =212567a(24) =255073a(25) =303651a(26) =358853a(27) =421255a(28) =491457a(29) =570083