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 A366657 #15 Jan 09 2024 18:46:24
%S A366657 3,13,84,800,4356,51792,351120,3100240,17041416,211053040,1494039792,
%T A366657 12611914848,73234343952,794382536272,5936210280000,60037292774400,
%U A366657 282937726148616,3264911394064320,24128875076496960,208532141890460960,1225825603154905104
%N A366657 Sum of the divisors of 8^n+1.
%H A366657 Max Alekseyev, <a href="/A366657/b366657.txt">Table of n, a(n) for n = 0..502</a>
%F A366657 a(n) = sigma(8^n+1) = A000203(A062395(n)).
%F A366657 a(n) = A069061(3*n). - _Max Alekseyev_, Jan 09 2024
%e A366657 a(4)=4356 because 8^4+1 has divisors {1, 17, 241, 4097}.
%p A366657 a:=n->numtheory[sigma](8^n+1):
%p A366657 seq(a(n), n=0..100);
%t A366657 DivisorSigma[1, 8^Range[0,20]+1] (* _Paul F. Marrero Romero_, Nov 19 2023 *)
%Y A366657 Cf. A062395, A000203, A057936, A274905, A366653, A366655, A366656, A366658.
%Y A366657 Cf. A069061, A366578, A366607, A366617, A366629, A366638, A366666, A366668, A366689, A366715.
%K A366657 nonn
%O A366657 0,1
%A A366657 _Sean A. Irvine_, Oct 15 2023