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A127572
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Triangle, T(n,k) = sigma(k) * n/k if k|n, T(n,k) = 0 otherwise.
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0
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1, 2, 3, 3, 0, 4, 4, 6, 0, 7, 5, 0, 0, 0, 6, 6, 9, 8, 0, 0, 12, 7, 0, 0, 0, 0, 0, 8, 8, 12, 0, 14, 0, 0, 0, 15, 9, 0, 12, 0, 0, 0, 0, 0, 13, 10, 15, 0, 0, 12, 0, 0, 0, 0, 18
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..55.
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FORMULA
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A126988 * M, where M = an infinite matrix with sigma(n) in the main diagonal and the rest zeros.
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EXAMPLE
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First few rows of the triangle are:
1;
2, 3;
3, 0, 4;
4, 6, 0, 7;
5, 0, 0, 0, 6;
6, 9, 8, 0, 0, 12;
...
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CROSSREFS
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Main diagonal = sigma(n), A000203; row sums = A060640.
Cf. A126988.
Sequence in context: A026932 A087401 A192498 * A021815 A075255 A135498
Adjacent sequences: A127569 A127570 A127571 * A127573 A127574 A127575
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KEYWORD
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nonn,tabl
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AUTHOR
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Gary W. Adamson, Jan 19 2007
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EXTENSIONS
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Edited by Franklin T. Adams-Watters, Aug 24 2011
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STATUS
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approved
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