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) =3a(4) =8a(5) =21a(6) =49a(7) =105a(8) =210a(9) =399a(10) =729a(11) =1293a(12) =2242a(13) =3821a(14) =6427a(15) =10703a(16) =17690a(17) =29073a(18) =47579a(19) =77621a(20) =126340a(21) =205291a(22) =333171a(23) =540233a(24) =875428a(25) =1417961a(26) =2295989a(27) =3716875a(28) =6016140a(29) =9736669