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) =9a(4) =36a(5) =108a(6) =268a(7) =591a(8) =1201a(9) =2303a(10) =4232a(11) =7534a(12) =13096a(13) =22357a(14) =37649a(15) =62749a(16) =103772a(17) =170616a(18) =279300a(19) =455747a(20) =741905a(21) =1205651a(22) =1956816a(23) =3173114a(24) =5142096a(25) =8329033a(26) =13486753a(27) =21833361a(28) =35339796a(29) =57195108