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 A330444 #10 Dec 15 2019 08:38:16
%S A330444 1,2,8,44,332,2852,28268,330164,4371452,62867492,980090828,
%T A330444 16792404884,316446118172,6484254233732,142335512881388,
%U A330444 3299266086185204,80092968046706492,2040940536907449572,55097942635383719948,1586719679112182359124
%N A330444 a(n) = Sum_{k=1..n} Stirling2(n,k) * (k-1)! * phi(k), where phi = A000010.
%H A330444 Vaclav Kotesovec, <a href="/A330444/b330444.txt">Table of n, a(n) for n = 1..420</a>
%F A330444 a(n) ~ 3 * n! / (Pi^2 * (log(2))^(n+1)).
%t A330444 Table[Sum[StirlingS2[n, k] * (k-1)! * EulerPhi[k], {k, 1, n}], {n, 1, 20}]
%o A330444 (PARI) a(n) = sum(k=1, n, stirling(n, k, 2)*(k-1)!*eulerphi(k)); \\ _Michel Marcus_, Dec 15 2019
%Y A330444 Cf. A000010, A330351, A330353.
%K A330444 nonn
%O A330444 1,2
%A A330444 _Vaclav Kotesovec_, Dec 15 2019