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 A055708 Numbers n such that n - 1 | sigma(n). 4
 2, 3, 10, 136, 32896, 2147516416 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(7) > 10^13. - Giovanni Resta, Jul 13 2015 LINKS MATHEMATICA Do[ If[ Mod[ DivisorSigma[1, n], n - 1] == 0, Print[n] ], {n, 2, 10^8} ] PROG (PARI) is(n)=sigma(n)%(n-1)==0 \\ Anders HellstrÃ¶m, Aug 15 2015 CROSSREFS Cf. A000203, A045768, A056006. Sequence in context: A076927 A064647 A119810 * A162647 A132536 A322067 Adjacent sequences:  A055705 A055706 A055707 * A055709 A055710 A055711 KEYWORD nonn,more AUTHOR Robert G. Wilson v, Dec 04 2000 EXTENSIONS a(6) from Donovan Johnson, Nov 15 2009 STATUS approved

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Last modified December 10 14:27 EST 2019. Contains 329896 sequences. (Running on oeis4.)