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 A338647 #9 Apr 22 2021 09:06:33
%S A338647 1,2,4,7,16,22,64,92,223,342,1024,1132,4096,5462,13534,21937,65536,
%T A338647 70978,262144,333472,890590,1398102,4194304,4528402,16236031,22369622,
%U A338647 57522106,88435312,268435456,272976502,1073741824,1431677702,3679303390,5726623062,16490405374,18543422953
%N A338647 a(n) = Sum_{k=1..n} 2^(k/gcd(n,k) - 1).
%F A338647 a(n) = Sum_{d|n} A054432(d).
%t A338647 Table[Sum[2^(k/GCD[n, k] - 1), {k, 1, n}], {n, 1, 36}]
%o A338647 (PARI) a(n) = sum(k=1, n, 2^(k/gcd(n,k) - 1)); \\ _Michel Marcus_, Apr 22 2021
%Y A338647 Cf. A011782, A034738, A054432, A057661, A130586.
%K A338647 nonn
%O A338647 1,2
%A A338647 _Ilya Gutkovskiy_, Apr 22 2021