a(n) = n^4/2 - n^3 + 3*n^2/2 - n + 1 = (n^2 + 1)*(n^2 - 2*n + 2)/2.

Terms

a(0) =1a(1) =1a(2) =5a(3) =25a(4) =85a(5) =221a(6) =481a(7) =925a(8) =1625a(9) =2665a(10) =4141a(11) =6161a(12) =8845a(13) =12325a(14) =16745a(15) =22261a(16) =29041a(17) =37265a(18) =47125a(19) =58825a(20) =72581a(21) =88621a(22) =107185a(23) =128525a(24) =152905a(25) =180601a(26) =211901a(27) =247105a(28) =286525a(29) =330485