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Search: id:A059967
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| 1, 9, 117, 1785, 29799, 527085, 9706503, 184138713, 3573805950, 70625252863, 1416298046436, 28748759731965, 589546754316126, 12195537924351375, 254184908607118800, 5332692942907262361, 112524941404978156215
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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S. Heubach, N. Y. Li and T. Mansour, Staircase tilings and k-Catalan structures, Discrete Math., 308 (2008), 5954-5964.
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FORMULA
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G.f. A(x) satisfies A=x+A^9. a(n) = (C(kn, n)/((k-1)n+1), k=9).
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MAPLE
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with(combinat): for n from 1 to 40 do printf(`%d, `, binomial(9*n, n)/((9-1)*n+1)) od:
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CROSSREFS
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Related algebraic sequences concerning trees: strictly k-ary trees (A000108: s=x+s^2, A001263: s=(x, y)+(x, s)+(s, y)+(s, s))), (A001764: s=x+s^3), (A002293: s=x+s^4), (A002294: s=x+s^5), (A002295: s=x+s^6), (A002296: s=x+s^7), (A007556: s=x+s^8), at most k-ary trees (A001006: s=x+xs+xs^2), (A036765-A036769, s=x+xs^2....+xs^k, k=3, 4, 5, 6, 7).
Sequence in context: A022607 A139740 A062994 this_sequence A027396 A113344 A081629
Adjacent sequences: A059964 A059965 A059966 this_sequence A059968 A059969 A059970
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KEYWORD
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base,nonn
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AUTHOR
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Claude Lenormand (claude.lenormand(AT)free.fr), Mar 05 2001
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Mar 15 2001
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