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Search: id:A129441
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| A129441 |
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Generating function in rational polynomials from Billey-Warrington paper for q=1:p(x, q) = (-1 + q^2*x^2 + q^3*x^3)/((1 + q*x + q^2*x^2)*(-1 + x + q*x + q^2*x^2 + q^2*x^3 - q^4*x^4)). |
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+0
1
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| 1, 1, 2, 7, 16, 39, 100, 248, 618, 1546, 3858, 9631, 24049, 60041, 149903, 374266, 934427, 2332981, 5824753, 14542648, 36308602, 90651625, 226329747, 565077072, 1410826915, 3522409024, 8794392287, 21956943442, 54819861280, 136868649264
(list; graph; listen)
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OFFSET
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1,3
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REFERENCES
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Sara Billey, Gregory Warrington,Kazhdan-Lusztig Polynomials for 321-hexagon-avoiding permutations, J. of Algebraic Combinatorics, page 132; http://www.math.washington.edu/~billey/
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FORMULA
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a(n) =Expansion of((-1+q^2*x^2+q^3*x^3)/((1+q*x+q^2*x^2)*(-1+x+q*x+q^2*x^2+q^2*x^3-q^4*x^4))) for q=1
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MATHEMATICA
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p[x_, q_] = (-1 + q^2*x^2 + q^3*x^3)/((1 + q*x + q^2*x^2)*(-1 + x + q*x + q^2*x^2 + q^2*x^3 - q^4*x^4)); Table[ SeriesCoefficient[Series[p[x, 1], {x, 0, 30}], n], {n, 0, 30}]
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CROSSREFS
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Sequence in context: A131405 A042243 A041887 this_sequence A093971 A065497 A131727
Adjacent sequences: A129438 A129439 A129440 this_sequence A129442 A129443 A129444
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KEYWORD
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nonn,uned
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 08 2007
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