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Numbers k such that A000203(k) = sigma(k) is not divisible by 6.
1

%I #16 Jan 29 2017 07:25:41

%S 1,2,3,4,7,8,9,12,13,16,18,19,21,25,27,28,31,32,36,37,39,43,48,49,50,

%T 52,57,61,63,64,67,72,73,75,76,79,81,84,91,93,97,98,100,103,108,109,

%U 111,112,117,121,124,127,128,129,133,139,144,148,151,156,157,162,163,169

%N Numbers k such that A000203(k) = sigma(k) is not divisible by 6.

%C Positions of nonzero terms in A084301. - _Ivan Neretin_, Jan 26 2017

%H Ivan Neretin, <a href="/A097503/b097503.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[170], ! Divisible[DivisorSigma[1, #], 6] &] (* _Ivan Neretin_, Jan 26 2017 *)

%o (PARI) isok(n) = (sigma(n) % 6) != 0; \\ _Michel Marcus_, Jan 26 2017

%Y Cf. A000203, A084301.

%Y Complement of A074627.

%K nonn

%O 1,2

%A _Labos Elemer_, Aug 23 2004

%E Definition corrected by _Ivan Neretin_, Jan 26 2017