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) =13a(4) =44a(5) =122a(6) =292a(7) =631a(8) =1267a(9) =2411a(10) =4408a(11) =7820a(12) =13560a(13) =23109a(14) =38867a(15) =64721a(16) =106964a(17) =175782a(18) =287660a(19) =469275a(20) =763795a(21) =1241071a(22) =2014128a(23) =3265848a(24) =5292144a(25) =8571817a(26) =13879587a(27) =22468981a(28) =36368252a(29) =58859186