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Expansion of c(x^2-x^3), c(x) the g.f. of A000108.
1

%I #4 Feb 20 2015 18:03:21

%S 1,0,-1,1,2,-4,-3,15,-1,-51,42,154,-274,-372,1341,405,-5599,2783,

%T 20295,-27313,-61139,160797,124462,-767702,94964,3145986,-2930086,

%U -10956466,21290868,29513156,-114974111,-33473459,522016279,-279684579,-2031228003,2867285041,6493289367,-17791297065

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

%C Diagonal sums of A115179.

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

%F 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

%Y Cf. A115178.

%K easy,sign

%O 0,5

%A _Paul Barry_, Mar 14 2006