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 A277498 #8 Nov 10 2017 07:37:41
%S A277498 0,1,2,8,56,536,6528,96592,1683072,33760576,766283264,19417068032,
%T A277498 543351873536,16642224306176,553782090473472,19893884376859648,
%U A277498 767355755629215744,31631864049541107712,1387750771948607504384,64561526675221208563712
%N A277498 E.g.f.: -LambertW(-sin(x)).
%H A277498 G. C. Greubel, <a href="/A277498/b277498.txt">Table of n, a(n) for n = 0..385</a>
%F A277498 a(n) ~ (1-exp(-2))^(1/4) * (arcsin(exp(-1)))^(1/2-n) * exp(1/2-n) * n^(n-1).
%t A277498 CoefficientList[Series[-LambertW[-Sin[x]], {x, 0, 20}], x] * Range[0, 20]!
%o A277498 (PARI) x='x+O('x^50); concat([0], Vec(serlaplace(- lambertw(-sin(x))))) \\ _G. C. Greubel_, Nov 08 2017
%Y A277498 Cf. A238085, A277461, A277475, A277499, A277500.
%K A277498 nonn
%O A277498 0,3
%A A277498 _Vaclav Kotesovec_, Oct 18 2016