Constant term of the reduction by x^2->x+1 of the polynomial p(n,x) defined at Comments.

Terms

a(0) =1a(1) =0a(2) =8a(3) =27a(4) =72a(5) =160a(6) =323a(7) =610a(8) =1102a(9) =1929a(10) =3302a(11) =5562a(12) =9261a(13) =15292a(14) =25100a(15) =41023a(16) =66844a(17) =108684a(18) =176447a(19) =286158a(20) =463746a(21) =751165a(22) =1216298a(23) =1968982a(24) =3186937a(25) =5157720a(26) =8346608a(27) =13506435a(28) =21855312a(29) =35364184