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Search: id:A003162
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| A003162 |
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A binomial coefficient summation.
(Formerly M2597)
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+0
2
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| 1, 1, 1, 3, 6, 19, 49, 163, 472, 1626, 5034, 17769, 57474, 206487, 688881, 2508195, 8563020, 31504240, 109492960, 406214878, 1432030036, 5349255726, 19077934506, 71672186953, 258095737156, 974311431094, 3537275250214, 13408623649893
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Problem E2384, Amer. Math. Monthly, 81 (1974), 170-171.
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PROGRAM
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(PARI) a(n)=if(n<0, 0, sum(k=0, n\2, (binomial(n, k)-binomial(n, k-1))^3)/binomial(n, n\2)) /* Michael Somos Jun 02 2005 */
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CROSSREFS
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Cf. A003161.
Sequence in context: A148566 A148567 A148568 this_sequence A129417 A132335 A148569
Adjacent sequences: A003159 A003160 A003161 this_sequence A003163 A003164 A003165
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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).
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