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 A367788 #6 Dec 01 2023 15:59:37 %S A367788 1,1,1,2,7,308,1065372,5699432573835,742435596532024691458409520, %T A367788 1770094160863794205114840009375146894748207874734794924 %N A367788 Let b(0) = 1, b(n) = Sum_{k=0..n-1} b(k) / b(n-k-1), then a(n) is the denominator of b(n). %C A367788 The next term is too large to include. %F A367788 G.f. for fractions satisfies: 1 / Sum_{n>=0} b(n) * x^n = 1 - x * Sum_{n>=0} x^n / b(n). %e A367788 1, 1, 2, 7/2, 44/7, 3459/308, 21398845/1065372, 204701870532176/5699432573835, ... %t A367788 b[0] = 1; b[n_] := b[n] = Sum[b[k]/b[n - k - 1], {k, 0, n - 1}]; a[n_] := Denominator[b[n]]; Table[a[n], {n, 0, 9}] %Y A367788 Cf. A000108, A022857, A022858, A073834, A367787 (numerators). %K A367788 nonn,frac %O A367788 0,4 %A A367788 _Ilya Gutkovskiy_, Nov 30 2023