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%I #22 Aug 15 2015 09:14:04
%S 2,3,10,136,32896,2147516416
%N Numbers n such that n - 1 | sigma(n).
%C a(7) > 10^13. - _Giovanni Resta_, Jul 13 2015
%t Do[ If[ Mod[ DivisorSigma[1, n], n - 1] == 0, Print[n] ], {n, 2, 10^8} ]
%o (PARI) is(n)=sigma(n)%(n-1)==0 \\ _Anders Hellström_, Aug 15 2015
%Y Cf. A000203, A045768, A056006.
%K nonn,more
%O 1,1
%A _Robert G. Wilson v_, Dec 04 2000
%E a(6) from _Donovan Johnson_, Nov 15 2009
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