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 A059491 Expansion of generating function A_{QT}^(1)(4n;3). 1
 1, 1, 6, 189, 30618, 25332021, 106698472452, 2283997201168644, 248218139523497121576, 136861610819571430116630660, 382684747771430768732371981946100, 5424628155237728987530088501811168904125, 389729317367139375014273384868937660572301897500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS G. C. Greubel, Table of n, a(n) for n = 0..50 G. Kuperberg, Symmetry classes of alternating-sign matrices under one roof, arXiv:math/0008184 [math.CO], 2000-2001 [Th. 5]. FORMULA a(n) = 3^(n*(n-1)/2)*A005130(n). a(n+1) is the Hankel transform of A097188. Odd terms occur in a(n+1) at positions given by 2*A000975(n). - Paul Barry, Feb 09 2007 MATHEMATICA f[n_] := Product[(3 k + 1)!/(n + k)!, {k, 0, n - 1}]; Table[3^(n*(n - 1)/2)*f[n], {n, 0, 20}] (* G. C. Greubel, Sep 10 2017 *) CROSSREFS Sequence in context: A324094 A129046 A222016 * A024279 A350873 A182788 Adjacent sequences: A059488 A059489 A059490 * A059492 A059493 A059494 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Feb 04 2001 STATUS approved

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Last modified December 4 06:57 EST 2023. Contains 367557 sequences. (Running on oeis4.)