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Search: id:A059338
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| A059338 |
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a(n) = sum (from k=1 to n) k^5*(n choose k). |
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+0
3
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| 1, 34, 342, 2192, 11000, 47232, 181888, 646144, 2156544, 6848000, 20877824, 61526016, 176171008, 492126208, 1345536000, 3610247168, 9526771712, 24769069056, 63546720256, 161087488000, 403925630976, 1002841309184
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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Finding a closed form for the sum was Problem 541 in the Fall 2000 issue of The Pentagon (official journal of Kappa Mu Epsilon).
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FORMULA
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The closed form comes from starting with (1+x)^n and repeatedly differentiating and multiplying by x. After five differentiations, substitute x=1 and get a(n) = 2^(n-5)*n^2*(n^3+10n^2+15n-10)
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MAPLE
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with(combinat): for n from 1 to 70 do printf(`%d, `, sum(k^5*binomial(n, k), k=1..n)) od:
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CROSSREFS
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Sequence in context: A027006 A101092 A034978 this_sequence A135243 A033914 A107917
Adjacent sequences: A059335 A059336 A059337 this_sequence A059339 A059340 A059341
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KEYWORD
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nonn,easy
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AUTHOR
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Pat Costello (matcostello(AT)acs.eku.edu), Jan 26 2001
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jan 29 2001
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