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 A350224 #11 Dec 20 2021 09:47:13
%S A350224 1,3,25,242,3038,45981,817445,16714015,386682183,9990395075,
%T A350224 285173906017,8913939944658,302838320218733,11111330886027346,
%U A350224 437880557043106024,18446463023081162520,827233956902648749749,39346258081658580861101
%N A350224 a(n) = Sum_{k=1..n} (-1)^(k+1) * floor((n/k)^n).
%t A350224 a[n_] := Sum[(-1)^(k + 1)*Floor[(n/k)^n], {k, 1, n}]; Array[a, 18] (* _Amiram Eldar_, Dec 20 2021 *)
%o A350224 (PARI) a(n) = sum(k=1, n, (-1)^(k+1)*(n^n\k^n));
%Y A350224 Cf. A344724, A347416, A350221, A350222, A350223.
%K A350224 nonn
%O A350224 1,2
%A A350224 _Seiichi Manyama_, Dec 20 2021