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 A343473 #6 Apr 16 2021 15:47:20 %S A343473 1,1,0,-4,0,16,108,-64,-864,-2660,-22464,33968,272268,1217152,4629312, %T A343473 68208188,-98077824,-1089798320,-5246016084,-32436365248, %U A343473 -180561473568,-3404617719332,5203858765248,55902314446832,354805454664396,2229923884913920 %N A343473 G.f.: 1 + (1*x)/(1 + (2*x)^2/(1 + (3*x)^3/(1 + (4*x)^4/(1 + (5*x)^5/(1 + ...))))). %o A343473 (PARI) a(n) = my(A=1+O(x)); for(i=1, n, A=1+((n-i+1)*x)^(n-i+1)/A); polcoef(A, n); %Y A343473 Cf. A343420, A343427. %K A343473 sign %O A343473 0,4 %A A343473 _Seiichi Manyama_, Apr 16 2021