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Search: id:A139714
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| A139714 |
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Sum_{ k >= 0} binomial(n,5*k+2). |
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+0
4
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| 0, 0, 1, 3, 6, 10, 15, 22, 36, 72, 165, 385, 859, 1807, 3614, 6995, 13380, 25773, 50559, 101118, 204820, 416405, 843756, 1698458, 3396916, 6765175, 13455325, 26789257, 53457121, 106914242, 214146295, 429124630, 859595529, 1720537327, 3441074654
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 14 2009: (Start)
M^n * [1,0,0,0,0] = [A139398(n), A139761(n), A139748(n), a(n), A133476(n)]
where M = a 5*5 matrix [1,1,0,0,0; 0,1,1,0,0; 0,0,1,1,0; 0,0,0,1,1; 1,0,0,0,1]
Sum of terms = 2^n. Example: M^6 = [7, 15, 20, 15, 7], sum = 2^6 = 64. (End)
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FORMULA
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G.f.:-x^2*(x-1)^2/((2*x-1)*(x^4-2*x^3+4*x^2-3*x+1)) [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 12 2009]
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CROSSREFS
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Sequence in context: A122047 A137358 A143963 this_sequence A063542 A122554 A111734
Adjacent sequences: A139711 A139712 A139713 this_sequence A139715 A139716 A139717
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jun 13 2008
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