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 A193337 #18 Mar 30 2024 03:01:44
%S A193337 1,4,1,8,4,4,1,24,14,13,4,8,8,4,4,32,13,56,6,32,1,13,4,24,32,32,6,8,
%T A193337 24,13,1,104,4,40,4,112,20,24,8,78,32,4,12,32,56,13,4,32,80,128,13,57,
%U A193337 40,24,13,24,6,78,24,32,32,4,14,128,32,13,18,104,4,13,13,336,38,80,32,48,4,32,6,128,133
%N A193337 Sum of odd divisors of sigma(n).
%C A193337 sigma(n) = sum of divisors of n: A000203 (also called sigma_1(n)).
%H A193337 Antti Karttunen, <a href="/A193337/b193337.txt">Table of n, a(n) for n = 1..16384</a>
%H A193337 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%H A193337 <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>.
%F A193337 a(n) = A000593(A000203(n)). - _Michel Marcus_, Jan 14 2014
%F A193337 a(n) + A193336(n) = A051027(n). - _Antti Karttunen_, Nov 18 2017
%F A193337 a(n) = A051027(n) if and only if n is in A028982. - _Amiram Eldar_, Mar 30 2024
%e A193337 a(8) = 24 because sigma(8) = 15 and the sum of the 4 odd divisors { 1, 3, 5, 15} is 24.
%t A193337 Table[Total[Select[Divisors[DivisorSigma[1,n]], OddQ[ # ]&]], {n, 60}]
%o A193337 (PARI) a(n) = sumdiv(sigma(n), d, (d%2)*d); \\ _Michel Marcus_, Jan 14 2014
%Y A193337 Cf. A000203, A028982, A051027, A193335, A193336.
%K A193337 nonn
%O A193337 1,2
%A A193337 _Michel Lagneau_, Jul 23 2011
%E A193337 More terms from _Antti Karttunen_, Nov 18 2017