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 A078118 n+1 does not divide sigma(n!). 1

%I #10 Feb 16 2019 06:54:16

%S 1,6,22,25,28,30,40,42,46,52,58,60,68,70,72,78,87,88,96,98,102,105,

%T 106,112,114,122,126,128,130,133,138,145,148,150,156,162,166,172,178,

%U 182,190,192,196,198,212,213,217,218,222,225,226,228,232,238,240,250,262

%N n+1 does not divide sigma(n!).

%H Vaclav Kotesovec, <a href="/A078118/b078118.txt">Table of n, a(n) for n = 1..8822</a>

%H Vaclav Kotesovec, <a href="/A078118/a078118.jpg">Plot of a(n)/n for n = 1..8000</a>

%F a(n) seems to be asymptotic to c*n with c=4.8....

%t Select[Range[300], Not[Divisible[DivisorSigma[1, #!], # + 1]] &] (* _Vaclav Kotesovec_, Feb 16 2019 *)

%Y Cf. A062569.

%K nonn

%O 1,2

%A _Benoit Cloitre_, Dec 05 2002

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Last modified February 22 22:43 EST 2024. Contains 370265 sequences. (Running on oeis4.)