a(n) = n*2^n + 2*n^2 + 1.

Terms

a(0) =1a(1) =5a(2) =17a(3) =43a(4) =97a(5) =211a(6) =457a(7) =995a(8) =2177a(9) =4771a(10) =10441a(11) =22771a(12) =49441a(13) =106835a(14) =229769a(15) =491971a(16) =1049089a(17) =2228803a(18) =4719241a(19) =9962195a(20) =20972321a(21) =44041075a(22) =92275657a(23) =192939043a(24) =402654337a(25) =838862051a(26) =1744831817a(27) =3623880115a(28) =7516194337