A082092 - OEIS

%I #12 Jul 18 2019 09:58:49

%S 6,10,14,15,20,21,22,24,26,27,28,30,33,34,35,38,39,40,42,44,45,46,49,

%T 51,54,55,56,57,58,60,62,63,65,66,68,69,70,74,76,77,78,82,85,86,87,88,

%U 91,92,93,94,95,96,99,102,104,105,106,108,110,111,114,115,116,117,118,119

%N Composite k such that d(k) < d(sigma(k)), i.e., A000005(k) < A000005(A000203(k)).

%C Not identical with A069116.

%H Amiram Eldar, <a href="/A082092/b082092.txt">Table of n, a(n) for n = 1..10000</a>

%e For n=27: d(27)=4, sigma(27) = 1 + 3 + 9 + 27 = 40, d(40) = 8 > d(27);

%e 27 is not in A069116.

%t df[x_] := Sign[ -DivisorSigma[0, x]+DivisorSigma[0, DivisorSigma[1, x]]] Do[s=df[n]; If[Equal[s, 1]&&!PrimeQ[n], Print[n]], {n, 1, 1000}]

%Y Cf. A000005, A000203, A037197, A069116, A073803, A073804.

%K nonn

%O 1,1

%A _Labos Elemer_, Apr 10 2003