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) =7a(4) =18a(5) =41a(6) =84a(7) =161a(8) =294a(9) =519a(10) =894a(11) =1513a(12) =2528a(13) =4185a(14) =6882a(15) =11263a(16) =18370a(17) =29889a(18) =48548a(19) =78761a(20) =127670a(21) =206831a(22) =334942a(23) =542257a(24) =877728a(25) =1420561a(26) =2298914a(27) =3720151a(28) =6019794a(29) =9740729