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A180958 Diagonal sums of generalized Narayana triangle A180957. 1
1, 1, 2, 2, 2, -1, -8, -25, -57, -114, -202, -322, -447, -496, -271, 625, 2914, 7762, 16834, 32063, 54760, 83319, 108375, 103726, 11110, -282498, -973439, -2366432, -4869919, -8903455, -14604094 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (2,1,-3,-1)

FORMULA

G.f.: ( 1-x-x^2 ) / ( (1+x)*(x^3+2*x^2-3*x+1) ).

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

CROSSREFS

Sequence in context: A086612 A128207 A306707 * A295854 A230630 A037867

Adjacent sequences:  A180955 A180956 A180957 * A180959 A180960 A180961

KEYWORD

easy,sign

AUTHOR

Paul Barry, Sep 28 2010

STATUS

approved

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Last modified August 19 08:17 EDT 2019. Contains 326115 sequences. (Running on oeis4.)