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Numbers n such that sigma(n)*7 < sigma(n-1) + sigma(n+1).
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%I #6 Jul 17 2013 01:14:34

%S 41902660799,41902660801,48886437599,53542288799,55870214401,

%T 62853991199,73329656401,80313433201,96376119841,97772875199,

%U 97772875201,101264763599,107084577599,107221514401,118356638399,118356638401,125707982401,128501493121,135019684799

%N Numbers n such that sigma(n)*7 < sigma(n-1) + sigma(n+1).

%C Conjecture: the sequence is infinite.

%H Giovanni Resta, <a href="/A227387/b227387.txt">Table of n, a(n) for n = 1..100</a>

%Y Cf. A000203, A072828.

%K nonn

%O 1,1

%A _Alex Ratushnyak_, Jul 09 2013

%E a(7)-a(19) from _Giovanni Resta_, Jul 15 2013