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A127527
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Triangle T(n,k)= tau(k)*phi(n/k) if k|n, else T(n,k)=0.
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2
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1, 1, 2, 2, 0, 2, 2, 2, 0, 3, 4, 0, 0, 0, 2, 2, 4, 2, 0, 0, 4, 6, 0, 0, 0, 0, 0, 2, 4, 4, 0, 3, 0, 0, 0, 4, 6, 0, 4, 0, 0, 0, 0, 0, 3, 4, 8, 0, 0, 2, 0, 0, 0, 0, 4
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OFFSET
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1,3
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COMMENTS
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Tau is the number of divisors A000005, and phi the Euler totient A000010.
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LINKS
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FORMULA
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EXAMPLE
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First few rows of the triangle are:
1;
1, 2;
2, 0, 2;
2, 2, 0, 3;
4, 0, 0, 0, 2;
2, 4, 2, 0, 0, 4;
6, 0, 0, 0, 0, 0, 2;
4, 4, 0, 3, 0, 0, 0, 4;
...
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MAPLE
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A127527 := proc(n, k) if n mod k = 0 then numtheory[tau](k)*numtheory[phi](n/k) ; else 0; end if; end proc: # R. J. Mathar, Apr 11 2011
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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