a(n) = 16*n^4 + 32*n^3 + 36*n^2 + 20*n + 3.

Terms

a(0) =3a(1) =107a(2) =699a(3) =2547a(4) =6803a(5) =15003a(6) =29067a(7) =51299a(8) =84387a(9) =131403a(10) =195803a(11) =281427a(12) =392499a(13) =533627a(14) =709803a(15) =926403a(16) =1189187a(17) =1504299a(18) =1878267a(19) =2318003a(20) =2830803a(21) =3424347a(22) =4106699a(23) =4886307a(24) =5772003a(25) =6773003a(26) =7898907a(27) =9159699a(28) =10565747