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Search: id:A100363
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| A100363 |
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Numbers n such that the numbers of divisors of n,n+1 and n+2 are k,2k,4k respectively for some k. |
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+0
4
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| 193, 397, 454, 457, 613, 614, 661, 757, 758, 997, 998, 1093, 1237, 1238, 1453, 1478, 1657, 1681, 1766, 2137, 2341, 2413, 2455, 2593, 2917, 2918, 2942, 2966, 3217, 3334, 3494, 3589, 4021, 4177, 4183, 4406, 4621, 5143, 5233, 5965, 6121, 6133, 6134, 6193
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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n=193,195,195 have 2,4,8 divisors.
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MATHEMATICA
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d0[x_] :=DivisorSigma[0, x]; ta={{0}}; Do[g=n; s=d0[n]; s1=d0[n+1]; s2=d0[n+2]; If[Equal[s1, 2*s]&&Equal[s2, 4*s], ta=Append[ta, n]; Print[{n, s, s1, s2}]], {n, 1, 10000}]; {ta=Delete[ta, 1], g}
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CROSSREFS
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Cf. A000005, A063446.
Sequence in context: A146824 A142453 A065213 this_sequence A142500 A113000 A105129
Adjacent sequences: A100360 A100361 A100362 this_sequence A100364 A100365 A100366
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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), Nov 19 2004
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