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A047917
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Triangular array a(n,k) = phi(n/k)*(n/k)^k*k!/n if k|n else 0 (1<=k<=n).
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0
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1, 1, 1, 2, 0, 2, 2, 2, 0, 6, 4, 0, 0, 0, 24, 2, 6, 8, 0, 0, 120, 6, 0, 0, 0, 0, 0, 720, 4, 8, 0, 48, 0, 0, 0, 5040, 6, 0, 36, 0, 0, 0, 0, 0, 40320, 4, 20, 0, 0, 384, 0, 0, 0, 0, 362880, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3628800, 4, 12, 64, 324, 0, 3840, 0, 0, 0, 0
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| J. E. A. Steggall, On the numbers of patterns which can be derived from certain elements, Mess. Math., 37 (1907), 56-61.
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EXAMPLE
| 1; 1,1; 2,0,2; 2,2,0,6; 4,0,0,0,24; 2,6,8,0,0,120; ...
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MATHEMATICA
| a[n_, k_] := If[ Divisible[n, k], EulerPhi[n/k]*(n/k)^k*k!/n, 0]; Flatten[ Table[ a[n, k], {n, 1, 12}, {k, 1, n}]](* From Jean-François Alcover, Feb 17 2012 *)
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CROSSREFS
| Divide n-th row of A047916 by n.
Row sums give A061417.
Sequence in context: A044943 A102395 A127504 * A144569 A000360 A023556
Adjacent sequences: A047914 A047915 A047916 * A047918 A047919 A047920
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KEYWORD
| nonn,tabl,nice,easy,changed
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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