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 A342933 #11 Jun 23 2021 13:50:24
%S A342933 1,9,80,654,6264,59760,665160,7565040,96929280,1286046720,18976083840,
%T A342933 286363123200,4775047200000,81792956044800,1515077749785600,
%U A342933 28898470215014400,594066352700620800,12467555729620992000,280797084422959104000,6460327992512249856000,157769680941941612544000
%N A342933 a(n) = n! * Sum_{k=1..n} k^2/floor(n/k).
%C A342933 In general, for m>=0, Sum_{k=1..n} k^m / floor(n/k) ~ n^(m+1) * (-1 + Sum_{j=2..m+2} zeta(j) / (m+1)).
%F A342933 a(n) ~ c * n^3 * n!, where c = Sum_{j>=1} (1 + 3*j*(j+1)) / (3*j^4*(j+1)^3) = (zeta(4) + zeta(3) + zeta(2))/3 - 1 = Pi^2/18 + Pi^4/270 + zeta(3)/3 - 1.
%t A342933 Table[n!*Sum[k^2/Floor[n/k], {k, 1, n}], {n, 1, 25}]
%t A342933 Table[n!*Sum[(Floor[n/j]*(1 + Floor[n/j])*(1 + 2*Floor[n/j]) - Floor[n/(1 + j)]*(1 + Floor[n/(1 + j)])*(1 + 2*Floor[n/(1 + j)]))/6/j, {j, 1, n}], {n, 1, 25}]
%Y A342933 Cf. A345683, A345684.
%K A342933 nonn
%O A342933 1,2
%A A342933 _Vaclav Kotesovec_, Jun 23 2021