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A115399 Expansion of c(x^2-x^3), c(x) the g.f. of A000108. 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Diagonal sums of A115179.

LINKS

Table of n, a(n) for n=0..37.

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

CROSSREFS

Cf. A115178.

Sequence in context: A271878 A259476 A271363 * A109429 A114894 A183169

Adjacent sequences:  A115396 A115397 A115398 * A115400 A115401 A115402

KEYWORD

easy,sign

AUTHOR

Paul Barry, Mar 14 2006

STATUS

approved

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Last modified October 22 07:29 EDT 2019. Contains 328315 sequences. (Running on oeis4.)