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) =10a(4) =25a(5) =55a(6) =110a(7) =207a(8) =373a(9) =652a(10) =1115a(11) =1877a(12) =3124a(13) =5157a(14) =8463a(15) =13830a(16) =22533a(17) =36635a(18) =59474a(19) =96451a(20) =156305a(21) =253176a(22) =409943a(23) =663625a(24) =1074120a(25) =1738345a(26) =2813115a(27) =4552162a(28) =7366033a(29) =11919007