A115399 Expansion of c(x^2-x^3), c(x) the g.f. of A000108.

1, 0, -1, 1, 2, -4, -3, 15, -1, -51, 42, 154, -274, -372, 1341, 405, -5599, 2783, 20295, -27313, -61139, 160797, 124462, -767702, 94964, 3145986, -2930086, -10956466, 21290868, 29513156, -114974111, -33473459, 522016279, -279684579, -2031228003, 2867285041, 6493289367, -17791297065

Offset: 0

Author

Paul Barry, Mar 14 2006

Keywords

• easy
• sign

Comments

Diagonal sums of A115179.

Crossrefs

Cf. A115178.

Formula

a(n)=sum{k=0..floor(n/2), (-1)^(n-k)*C(k)C(k,n-2k)}.

Conjecture: (n+2)*a(n) +(-n-2)*a(n-1) +4*(n-1)*a(n-2) +2*(-4*n+7)*a(n-3) +2*(2*n-5)*a(n-4)=0. - R. J. Mathar, Feb 20 2015