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 A120783 #18 Jun 13 2022 07:49:45
%S A120783 1,12,72,1728,10368,41472,248832,11943936,214990848,2579890176,
%T A120783 15479341056,371504185344,2229025112064,26748301344768,53496602689536,
%U A120783 1711891286065152,10271347716390912,369768517790072832
%N A120783 Denominators of partial sums of Catalan numbers scaled by powers of 1/12.
%C A120783 Numerators are given under A120782.
%C A120783 It appears that the terms of this sequence are denominators of the power series expansion of 1+sqrt(x) at x=3, scaled by 1/(2*sqrt(3)). - _Alexander R. Povolotsky_, Mar 01 2016
%H A120783 G. C. Greubel, <a href="/A120783/b120783.txt">Table of n, a(n) for n = 0..925</a>
%F A120783 a(n) = denominator(r(n)), with the rationals r(n) = Sum_{k=0..n} C(k)/12^k with C(k) = A000108(k) (Catalan numbers).
%t A120783 Denominator@ Table[Sum[CatalanNumber@ k/12^k, {k, 0, n}], {n, 0, 17}] (* _Michael De Vlieger_, Mar 03 2016 *)
%o A120783 (PARI) C(n) = binomial(2*n, n)/(n+1); \\ A000108
%o A120783 a(n) = denominator(sum(k=0, n, C(k)/12^k)); \\ _Michel Marcus_, Mar 02 2016
%Y A120783 Cf. A000108, A120782.
%K A120783 nonn,frac,easy
%O A120783 0,2
%A A120783 _Wolfdieter Lang_, Jul 20 2006