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 A067655 #15 Feb 02 2019 14:14:10
%S A067655 1,1,3,3,15,45,315,315,2835,14175,155925,467775,6081075,3869775,
%T A067655 638512875,638512875,10854718875,8881133625,1856156927625,
%U A067655 9280784638125,194896477400625,2143861251406875,2595200462229375
%N A067655 Denominators of the coefficients in exp(2x/(1-x)) power series.
%C A067655 Differs from A049606 at positions enumerated by A097324.
%D A067655 K. Knopp, Theory and application of infinite series, Dover, p. 547.
%D A067655 O. Perron, Über das infinitäre Verhalten der Koeffizienten einer gewissen Potenzreihe, Archiv d. Math. u. Phys. (3), Vol. 22, pp. 329-340, 1914.
%F A067655 a(n) is the denominator in Sum_{i=1..n} binomial(n-1, i-1)*2^i/i!.
%Y A067655 Cf. A067654.
%K A067655 nonn,frac
%O A067655 1,3
%A A067655 _Benoit Cloitre_, Feb 03 2002