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A015883
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Numbers k such that sigma(k) = sigma(k+13).
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15
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182, 782, 1965, 2486, 2678, 2685, 12141, 12441, 17342, 21242, 27686, 34905, 35505, 35853, 38662, 38985, 56732, 63578, 104342, 109461, 192933, 198909, 222122, 236966, 245349, 251654, 256322, 261885, 262238, 324441, 333909
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listen;
history;
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internal format)
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OFFSET
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1,1
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REFERENCES
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J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 182, p. 56, Ellipses, Paris 2008.
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LINKS
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MAPLE
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for n from 1 to q do if sigma(n+13)=sigma(n) then print(n); fi; od; end:
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MATHEMATICA
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Select[Range[350000], DivisorSigma[1, #]==DivisorSigma[1, # + 13] &] (* Vincenzo Librandi, Mar 10 2014 *)
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PROG
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CROSSREFS
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Cf. A002961, A007373, A015861, A015863, A015865, A015866, A015867, A015876, A015877, A015880, A015881, A015882, A181647.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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