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

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =22a(5) =48a(6) =96a(7) =181a(8) =327a(9) =573a(10) =982a(11) =1656a(12) =2760a(13) =4561a(14) =7491a(15) =12249a(16) =19966a(17) =32472a(18) =52728a(19) =85525a(20) =138615a(21) =224541a(22) =363598a(23) =588624a(24) =952752a(25) =1541953a(26) =2495331a(27) =4037961a(28) =6534022a(29) =10572768