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Search: id:A069970
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| A069970 |
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Numbers n such that sigma(reverse(n)) = sigma(reverse(n-1)) + sigma(reverse(n-2)). |
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+0
1
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| 3, 4, 352, 525, 532, 564, 572, 782, 3783, 5242, 5762, 5784, 7852, 7884, 31732, 38817, 41736, 46194, 52942, 57842, 61146, 63075, 67266, 68853, 95418
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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sigma(reverse(352)) = sigma(253) = 288 = 234 + 54 = sigma(153) + sigma(53) = sigma(reverse(352-1)) + sigma(reverse(352-2)).
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MATHEMATICA
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rev[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Select[Range[3, 10^5], DivisorSigma[1, rev[ # ]] == DivisorSigma[1, rev[ # - 1]] + DivisorSigma[1, rev[ # - 2]] &]
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CROSSREFS
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Sequence in context: A042485 A111315 A042711 this_sequence A094396 A059107 A025115
Adjacent sequences: A069967 A069968 A069969 this_sequence A069971 A069972 A069973
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KEYWORD
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base,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Apr 29 2002
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