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) =1a(3) =4a(4) =11a(5) =27a(6) =58a(7) =115a(8) =215a(9) =386a(10) =673a(11) =1149a(12) =1932a(13) =3213a(14) =5301a(15) =8696a(16) =14207a(17) =23143a(18) =37622a(19) =61071a(20) =99035a(21) =160486a(22) =259941a(23) =420889a(24) =681336a(25) =1102777a(26) =1784713a(27) =2888140a(28) =4673555a(29) =7562451