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) =2a(3) =19a(4) =102a(5) =377a(6) =1104a(7) =2777a(8) =6282a(9) =13155a(10) =25998a(11) =49153a(12) =89792a(13) =159681a(14) =278034a(15) =476131a(16) =804790a(17) =1346457a(18) =2234768a(19) =3686201a(20) =6051290a(21) =9897491a(22) =16143262a(23) =26275009a(24) =42698112a(25) =69304897a(26) =112393634a(27) =182155507a(28) =295080582a(29) =477850745