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 A188920 a(n) is the limiting term of the n-th column of the triangle in A188919. 2
 1, 1, 2, 4, 7, 13, 22, 38, 63, 105, 169, 274, 434, 686, 1069, 1660, 2548, 3897, 5906, 8911, 13352, 19917, 29532, 43605, 64056, 93715, 136499, 198059, 286233, 412199, 591455, 845851, 1205687, 1713286, 2427177, 3428611, 4829563, 6784550, 9505840, 13284849 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS A. M. Baxter, Algorithms for Permutation Statistics, Ph. D. Dissertation, Rutgers University, May 2011 Andrew M. Baxter and Lara K. Pudwell, Enumeration schemes for dashed patterns, arXiv preprint arXiv:1108.2642, 2011 MATHEMATICA b[u_, o_] := b[u, o] = Expand[If[u + o == 0, 1, Sum[b[u - j, o + j - 1]*x^(o + j - 1), {j, 1, u}] + Sum[If[u == 0, b[u + j - 1, o - j]*x^(o - j), 0], {j, 1, o}]]]; T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][ b[0, n]]; Take[T[40], 40] (* Jean-François Alcover, Sep 15 2018, after Alois P. Heinz in A188919 *) CROSSREFS Sequence in context: A192758 A085489 A101268 * A281362 A319111 A128768 Adjacent sequences:  A188917 A188918 A188919 * A188921 A188922 A188923 KEYWORD nonn AUTHOR N. J. A. Sloane, Apr 13 2011 EXTENSIONS More terms from Andrew Baxter, May 17 2011 a(30)-a(39) from Alois P. Heinz, Nov 14 2015 STATUS approved

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Last modified March 22 01:06 EDT 2019. Contains 321406 sequences. (Running on oeis4.)