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Search: id:A080372
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| A080372 |
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a(n) = smallest x such that quotient d(x)/d(x+1) equals n, where d()=A000005, the number of divisors. |
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+0
2
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| 2, 6, 12, 30, 112, 60, 192, 210, 180, 240, 13312, 420, 12288, 2112, 1008, 1320, 2162688, 1800, 786432, 2160, 4800, 15360
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n)=Min{x : d[x]/d[x+1]=n}
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EXAMPLE
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n = 17: a(17) = 2162688 = m, d[m] = 68,d[m+1] = 4,quotient = 17.
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MATHEMATICA
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t = Table[ 0, {50}]; Do[ s = DivisorSigma[0, n] / DivisorSigma[0, n+1]; If[ s < 51 && t[[s]] == 0, t[[s]] = n], {n, 1, 45000000}]; t
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CROSSREFS
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Cf. A000005, A080371.
Sequence in context: A095349 A022916 A073949 this_sequence A000650 A032178 A102881
Adjacent sequences: A080369 A080370 A080371 this_sequence A080373 A080374 A080375
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Feb 24 2003
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 27 2003
The sequence continues: ?, 2520, 6480, 61440, 6300, 8640, ?, 12240, ?, 7560, 64512, 1376256, 58320, 12600, ?, 8650752 ...
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