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 A348930 #11 Nov 04 2021 20:46:56
%S A348930 1,1,4,7,2,4,8,5,13,2,4,28,14,8,8,31,2,13,20,14,32,4,8,20,31,14,40,56,
%T A348930 10,8,32,7,16,2,16,91,38,20,56,10,14,32,44,28,26,8,16,124,19,31,8,98,
%U A348930 2,40,8,40,80,10,20,56,62,32,104,127,28,16,68,14,32,16,8,65,74,38,124,140,32,56,80,62,121,14,28
%N A348930 a(n) = A038502(sigma(n)), where A038502 is fully multiplicative with a(3) = 1, and a(p) = p for any other prime p.
%C A348930 Note that a(A005820(4)) = A005820(4) and a(A005820(6)) = A005820(6), i.e., the fourth and sixth 3-perfect numbers, 459818240 and 51001180160 are among the fixed points of this sequence, precisely because they are also terms of A323653. As the former factorizes as 459818240 = 256 * 5 * 7 * 19 * 37 * 73, it must follow that a(256)/256 * a(5)/5 * a(7)/7 * a(19)/19 * a(37)/37 * a(73)/73 = 1, because ratio a(n)/n is multiplicative. See also comments in A348738.
%H A348930 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A348930 Multiplicative with a(p^e) = A038502(1 + p + p^2 + ... + p^e).
%F A348930 a(n) = A038502(A000203(n)).
%F A348930 For all n >= 1, A000265(a(n)) = A336457(n).
%t A348930 s[n_] := n / 3^IntegerExponent[n, 3]; Table[s[DivisorSigma[1, n]], {n, 1, 100}] (* _Amiram Eldar_, Nov 04 2021 *)
%o A348930 (PARI)
%o A348930 A038502(n) = (n/3^valuation(n, 3));
%o A348930 A348930(n) = A038502(sigma(n));
%Y A348930 Cf. A000203, A000265, A005820, A038502, A323653, A348738, A348931, A348932.
%Y A348930 Cf. also A161942, A336457.
%K A348930 nonn,mult
%O A348930 1,3
%A A348930 _Antti Karttunen_, Nov 04 2021