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 A345030 #17 Jun 07 2021 09:09:20
%S A345030 1,3,11,70,633,7821,117709,2097684,43047545,1000010125,25937439391,
%T A345030 743008621422,23298085496173,793714780786669,29192926036832363,
%U A345030 1152921504875352376,48661191876077295937,2185911559749718388655,104127350297928227579629
%N A345030 a(n) = Sum_{k=1..n} n^(floor(n/k) - 1).
%H A345030 Seiichi Manyama, <a href="/A345030/b345030.txt">Table of n, a(n) for n = 1..387</a>
%F A345030 a(n) = [x^n] (1/(1 - x)) * Sum_{k>=1} x^k * (1 - x^k)/(1 - n*x^k).
%t A345030 a[n_] := Sum[n^(Floor[n/k] - 1), {k, 1, n}]; Array[a, 20] (* _Amiram Eldar_, Jun 06 2021 *)
%o A345030 (PARI) a(n) = sum(k=1, n, n^(n\k-1));
%Y A345030 Diagonal of A345032.
%Y A345030 Cf. A023037, A332533, A344551, A345036.
%K A345030 nonn
%O A345030 1,2
%A A345030 _Seiichi Manyama_, Jun 06 2021