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 A376049 #15 Jul 09 2025 05:05:40 %S A376049 1,4,20,1620,2626020,34479907828020,10699776394458828344981911620, %T A376049 228970429782836729250563232145698649718622958323963960420, %U A376049 314564746289621790478499809054644383073494124885364231904506529162346525698245870188461228508418377184391923418820 %N A376049 a(n) is the denominator of the sum S(n) defined in A376048. %H A376049 Alois P. Heinz, <a href="/A376049/b376049.txt">Table of n, a(n) for n = 0..11</a> %F A376049 a(n+1) = b(n+1)*a(n)^2 + a(n), with a(1) = 4, where b(n) is defined in A376048. %e A376049 The first few values of S(n) are 0/1, 3/4, 19/20, 1619/1620, 2626019/2626020, 34479907828019/34479907828020, ... %Y A376049 Cf. A000796, A375531, A375532, A376048. %K A376049 nonn,base,frac %O A376049 0,2 %A A376049 _N. J. A. Sloane_, Sep 13 2024 %E A376049 a(0)=1 prepended by _Alois P. Heinz_, Oct 18 2024