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 A308518 #6 Jun 03 2019 19:47:00
%S A308518 1,1,1,0,-4,-12,-3,150,744,525,-16799,-118280,-148289,4036802,
%T A308518 37244157,68676153,-1758280309,-20207442595,-49855713746,
%U A308518 1245931950070,17250366460410,53991885230741,-1330935478357842,-21705274324058996,-83339285813776419,2026672671500822591,38327819123289163864
%N A308518 Expansion of e.g.f. exp(1 - exp(1 - exp(x))).
%F A308518 a(n) = Sum_{k=0..n} (-1)^k*Stirling2(n,k)*A000587(k).
%F A308518 a(0) = 1; a(n) = -Sum_{k=1..n} binomial(n-1,k-1)*A000587(k)*a(n-k).
%t A308518 nmax = 26; CoefficientList[Series[Exp[1 - Exp[1 - Exp[x]]], {x, 0, nmax}], x] Range[0, nmax]!
%t A308518 Table[Sum[(-1)^k StirlingS2[n, k] BellB[k, -1], {k, 0, n}], {n, 0, 26}]
%t A308518 a[n_] := a[n] = -Sum[Binomial[n - 1, k - 1] BellB[k, -1] a[n - k], {k, 1, n}]; a[0] = 1; Table[a[n], {n, 0, 26}]
%Y A308518 Cf. A000258, A000587, A130410, A308519.
%K A308518 sign
%O A308518 0,5
%A A308518 _Ilya Gutkovskiy_, Jun 03 2019