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A127571
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Triangle, left column = phi(n), right border = sigma(n), row sums = n*d(n).
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0
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1, 1, 3, 2, 0, 4, 2, 3, 0, 7, 4, 0, 0, 0, 6, 2, 6, 4, 0, 0, 12, 6, 0, 0, 0, 0, 0, 8, 4, 6, 0, 7, 0, 0, 0, 15, 6, 0, 8, 0, 0, 0, 0, 0, 13, 4, 12, 0, 0, 6, 0, 0, 0, 0, 18
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OFFSET
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1,3
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COMMENTS
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Left column = phi(n), A000010; right border = sigma(n), A000203; row sums = d*d(n), A038040: (1, 4, 6, 12, 10, 24,...).
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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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A054523 * M, where M = an infinite lower triangular matrix with sigma(n), A000203, 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;
1, 3;
2, 0, 4;
2, 3, 0, 7;
4, 0, 0, 0, 6;
2, 6, 4, 0, 0, 12;
...
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CROSSREFS
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Cf. A000203, A000010, A038040, A054523.
Sequence in context: A088161 A005874 A129239 * A194662 A143612 A011231
Adjacent sequences: A127568 A127569 A127570 * A127572 A127573 A127574
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KEYWORD
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nonn,tabl,uned
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AUTHOR
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Gary W. Adamson, Jan 19 2007
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STATUS
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approved
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