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 A366577 #27 Jan 06 2024 12:13:08
%S A366577 2,3,4,6,4,6,8,6,8,24,12,12,8,6,16,48,4,24,16,12,8,72,16,6,64,24,16,
%T A366577 96,16,24,48,12,4,96,16,24,16,24,16,192,32,12,128,6,32,768,16,24,16,
%U A366577 24,128,384,16,12,32,96,64,192,16,12,128,12,32,4608,4,24,64
%N A366577 Number of divisors of 3^n+1.
%H A366577 Max Alekseyev, <a href="/A366577/b366577.txt">Table of n, a(n) for n = 0..691</a>
%F A366577 a(n) = sigma0(3^n+1) = A000005(A034472(n)).
%e A366577 a(4)=4 because 3^4+1 has divisors {1, 2, 41, 82}.
%p A366577 a:=n->numtheory[tau](3^n+1):
%p A366577 seq(a(n), n=0..100);
%t A366577 DivisorSigma[0,3^Range[0,100]+1] (* _Paolo Xausa_, Oct 15 2023 *)
%o A366577 (PARI) a(n) = numdiv(3^n+1); \\ _Michel Marcus_, Oct 14 2023
%Y A366577 Cf. A000005, A002592, A034472, A046798, A057935, A057941, A074476, A274909, A366575, A366578, A366579, A366580
%K A366577 nonn
%O A366577 0,1
%A A366577 _Sean A. Irvine_, Oct 13 2023