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

Terms

a(0) =1a(1) =1a(2) =9a(3) =29a(4) =75a(5) =165a(6) =331a(7) =623a(8) =1123a(9) =1963a(10) =3357a(11) =5651a(12) =9405a(13) =15525a(14) =25477a(15) =41633a(16) =67831a(17) =110281a(18) =179031a(19) =290339a(20) =470511a(21) =762111a(22) =1234009a(23) =1997639a(24) =3233305a(25) =5232745a(26) =8468001a(27) =13702853a(28) =22173123a(29) =35878413