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A123491
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Diagonal sums of number triangle A123490.
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2
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1, 2, 5, 10, 22, 48, 112, 274, 715, 1982, 5837, 18180, 59644, 205296, 739032, 2775180, 10846965, 44039754, 185391469, 807776198, 3637193474, 16900721824, 80939650552, 399061251246, 2023408865983, 10540656630118
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OFFSET
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0,2
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LINKS
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G. C. Greubel, Table of n, a(n) for n = 0..675
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FORMULA
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a(n) = Sum_{k=0..floor(n/2)} ((k+2)^(n-2k)+k)/(k+1).
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MATHEMATICA
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Table[Sum[((k + 2)^(n - 2 k) + k)/(k + 1), {k, 0, Floor[n/2]}], {n, 0, 50}] (* G. C. Greubel, Oct 14 2017 *)
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PROG
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(PARI) for(n=0, 25, print1(sum(k=0, floor(n/2), ((k + 2)^(n - 2 k) + k)/(k + 1)), ", ")) \\ G. C. Greubel, Oct 14 2017
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CROSSREFS
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Cf. A123490.
Sequence in context: A320650 A018109 A341020 * A329185 A232163 A166300
Adjacent sequences: A123488 A123489 A123490 * A123492 A123493 A123494
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry, Oct 01 2006
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STATUS
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approved
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