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) =21a(5) =44a(6) =85a(7) =156a(8) =276a(9) =476a(10) =806a(11) =1347a(12) =2230a(13) =3667a(14) =6001a(15) =9787a(16) =15923a(17) =25862a(18) =41955a(19) =68006a(20) =110170a(21) =178406a(22) =288828a(23) =467509a(24) =756636a(25) =1224469a(26) =1981455a(27) =3206301a(28) =5188161a(29) =8394896