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 A248150 #26 Aug 04 2023 15:47:05 %S A248150 3,6,7,11,12,14,15,19,21,22,23,24,27,28,30,31,33,35,38,39,42,43,44,46, %T A248150 47,48,51,54,55,56,57,59,60,62,63,65,66,67,69,70,71,75,76,77,78,79,83, %U A248150 84,85,86,87,88,91,92,93,94,95,96,99,102,103,105,107,108,110,111,112,114,115,118 %N A248150 Numbers whose sum of divisors (A000203) is divisible by 4. %C A248150 A subsequence of A028983 (even sum of divisors) which contains all numbers but the squares and twice the squares, so no term of this sequence is of that form, either. %C A248150 Any number having at least two odd prime factors to an odd power is in this sequence, therefore it has asymptotic density 1. - _M. F. Hasler_, Apr 26 2017 %H A248150 Amiram Eldar, <a href="/A248150/b248150.txt">Table of n, a(n) for n = 1..10000</a> %F A248150 a(n) ~ n. - _Charles R Greathouse IV_, Sep 01 2015 %t A248150 Select[Range[200],Divisible[DivisorSigma[1,#],4]&] (* _Harvey P. Dale_, Feb 20 2015 *) %o A248150 (PARI) for(n=1,999,sigma(n)%4||print1(n",")) %Y A248150 Cf. A000203, A028982, A028983, A248151. %Y A248150 First differs from A022544 by including 65. %K A248150 nonn %O A248150 1,1 %A A248150 _M. F. Hasler_, Oct 02 2014