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A159667
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For n >= 1, a(n) = A159666(n)/n.
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1
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1, 2, 6, 26, 133, 905, 6521, 57126, 544820, 5878219, 66851119, 881424550, 11803494823, 175906313032, 2767829058956, 47008174824136, 821285150996811, 15816596073011143, 308160754687446289, 6498330632792677804
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(n) is divisible by n, for all n >= 1.
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MATHEMATICA
| f[n_] := f[n] = Sum[Binomial[n, k] GCD[n, k] f[k - 1], {k, n}]; f[0] = 1; Table[f@n/n, {n, 22}] [From Robert G. Wilson v (rgwv(AT)rgwv.com), May 27 2009]
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CROSSREFS
| A159666
Sequence in context: A030850 A030951 A030876 * A030957 A030898 A002788
Adjacent sequences: A159664 A159665 A159666 * A159668 A159669 A159670
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet, Apr 19 2009
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), May 27 2009
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