%I #10 Aug 27 2020 17:08:20

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,17,18,19,20,21,22,23,25,26,28,29,

%T 30,31,33,34,35,37,38,39,41,42,43,44,46,47,50,51,52,53,55,57,58,59,60,

%U 61,62,65,66,67,68,69,70,71,73,74,75,76,77,78,79,82,83,85,86,87,88,89,91,92,93,94,95,97,101,102,103

%N Numbers k for which A003961(k) < 2*sigma(k).

%H Antti Karttunen, <a href="/A337379/b337379.txt">Table of n, a(n) for n = 1..20000</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%o (PARI)

%o A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

%o isA337379(n) = (A003961(n)<2*sigma(n));

%Y Cf. A000203, A003961, A286385.

%Y Cf. A337378 (complement).

%Y Positions of zeros in A337380.

%Y Cf. also A246281, A337382 (subsequences).

%K nonn

%O 1,2

%A _Antti Karttunen_, Aug 27 2020