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 A292920 #4 Sep 29 2017 07:19:29
%S A292920 1,-1,-3,167,262305,-19802585281,-111307539961183167,
%T A292920 66192452118355875767376767,5609362049224731266886822845131449345,
%U A292920 -87773600779729250264394909974880988558750376171521,-318955450227538853365057634352430260175496937997604285602324132863
%N A292920 a(n) = [x^n] 1/(1 + x/(1 - 2^n*x/(1 + 3^n*x/(1 - 4^n*x/(1 + 5^n*x/(1 - ...)))))), a continued fraction.
%F A292920 a(n) = A291207(n,n).
%t A292920 Table[SeriesCoefficient[1/(1 + ContinuedFractionK[-(-1)^k k^n x, 1, {k, 1, n}]), {x, 0, n}], {n, 0, 10}]
%Y A292920 Main diagonal of A291207.
%Y A292920 Cf. A291333.
%K A292920 sign
%O A292920 0,3
%A A292920 _Ilya Gutkovskiy_, Sep 26 2017