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A085045
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Smallest k such that tau(n + k) = tau (nk), or 0 if no such number exists, where tau = A000005.
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0
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2, 1, 5, 2, 3, 134, 3, 4, 11, 2, 3, 548, 2, 1, 3, 2, 5, 402, 2, 316, 1, 38, 3, 1236, 3, 1, 13, 2, 5, 1986, 2, 16, 1, 1, 19, 1644, 2, 1, 13, 716, 4, 1398, 3, 1, 15, 14, 11, 2472, 3, 10, 5, 2, 2, 1146, 23, 4, 1, 14, 3, 11028, 13, 4, 3, 2, 23, 1194, 2, 2, 9, 2
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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EXAMPLE
| a(4) = 2 as tau(4+2) = tau(6) = 4 and tau(4*2)= tau(8) = 4.
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MATHEMATICA
| f[n_] := Block[{k = 1}, While[ DivisorSigma[0, n + k] != DivisorSigma[0, n*k], k++ ]; k]; Table[ f[n], {n, 1, 80}]
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CROSSREFS
| Sequence in context: A127156 A205106 A144019 * A093664 A087620 A178913
Adjacent sequences: A085042 A085043 A085044 * A085046 A085047 A085048
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 20 2003
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EXTENSIONS
| Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Jun 25 2003
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