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 A110525 Expansion of 1/(1-x^2*c(3x)), c(x) the g.f. A000108. 2
 1, 0, 1, 3, 19, 141, 1180, 10593, 99712, 971067, 9702388, 98899638, 1024429861, 10752006033, 114097140757, 1222113460332, 13195550763793, 143470913825427, 1569448022488435, 17261100136608984, 190752895126918819 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Diagonal sums of A110518. LINKS G. C. Greubel, Table of n, a(n) for n = 0..930 FORMULA a(n) = Sum_{k=0..floor(n/2)} (k/(n-k))*C(2*n-3*k-1, n-2*k)*3^(n-2*k). MATHEMATICA Join[{1}, Table[Sum[(k/(n - k))*Binomial[2*n - 3*k - 1, n - 2*k]*3^(n - 2*k), {k, 0, Floor[n/2]}], {n, 1, 50}]] (* G. C. Greubel, Aug 30 2017 *) PROG (PARI) concat([1], for(n=1, 25, print1(sum(k=0, n\2, (k/(n - k))*binomial(2*n - 3*k - 1, n - 2*k)*3^(n - 2*k)), ", "))) \\ G. C. Greubel, Aug 30 2017 CROSSREFS Sequence in context: A025571 A221266 A082758 * A331716 A058859 A291964 Adjacent sequences:  A110522 A110523 A110524 * A110526 A110527 A110528 KEYWORD easy,nonn AUTHOR Paul Barry, Jul 24 2005 STATUS approved

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Last modified November 26 12:37 EST 2020. Contains 338639 sequences. (Running on oeis4.)