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A106355
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Number of compositions of n into 6 parts such that no two adjacent parts are equal.
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2
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2, 10, 30, 76, 168, 320, 580, 968, 1558, 2380, 3540, 5078, 7160, 9804, 13238, 17510, 22884, 29418, 37462, 47054, 58638, 72272, 88454, 107262, 129312, 154644, 183994, 217442, 255782, 299114, 348386, 403652, 466012, 535550, 613442, 699812, 796012
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OFFSET
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9,1
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LINKS
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A. Knopfmacher and H. Prodinger, On Carlitz compositions, European Journal of Combinatorics, Vol. 19, 1998, pp. 579-589.
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FORMULA
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G.f.: 2 *(16*x^12 +16*x^11 +31*x^10 +40*x^9 +53*x^8 +51*x^7 +51*x^6 +39*x^5 +31*x^4 +18*x^3 +9*x^2 +4*x+1) *x^9 / ((x^2-x+1) *(x^4+x^3+x^2+x+1) *(x^2+1) *(x^2+x+1)^2 *(x+1)^3 *(x-1)^6). - Alois P. Heinz, Sep 04 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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