This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A337379 #10 Aug 27 2020 17:08:20 %S A337379 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 A337379 30,31,33,34,35,37,38,39,41,42,43,44,46,47,50,51,52,53,55,57,58,59,60, %U A337379 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 A337379 Numbers k for which A003961(k) < 2*sigma(k). %H A337379 Antti Karttunen, <a href="/A337379/b337379.txt">Table of n, a(n) for n = 1..20000</a> %H A337379 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %H A337379 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %o A337379 (PARI) %o A337379 A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; %o A337379 isA337379(n) = (A003961(n)<2*sigma(n)); %Y A337379 Cf. A000203, A003961, A286385. %Y A337379 Cf. A337378 (complement). %Y A337379 Positions of zeros in A337380. %Y A337379 Cf. also A246281, A337382 (subsequences). %K A337379 nonn %O A337379 1,2 %A A337379 _Antti Karttunen_, Aug 27 2020