A078118 - OEIS

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A078118

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

1, 6, 22, 25, 28, 30, 40, 42, 46, 52, 58, 60, 68, 70, 72, 78, 87, 88, 96, 98, 102, 105, 106, 112, 114, 122, 126, 128, 130, 133, 138, 145, 148, 150, 156, 162, 166, 172, 178, 182, 190, 192, 196, 198, 212, 213, 217, 218, 222, 225, 226, 228, 232, 238, 240, 250, 262

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 1..8822

Vaclav Kotesovec, Plot of a(n)/n for n = 1..8000

FORMULA

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

MATHEMATICA

Select[Range[300], Not[Divisible[DivisorSigma[1, #!], # + 1]] &] (* Vaclav Kotesovec, Feb 16 2019 *)

CROSSREFS

Cf. A062569.