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 A133649 #19 Mar 23 2022 13:00:03
%S A133649 1,4,9,19,37,75,149,299,597,1195,2389,4779,9557,19115,38229,76459,
%T A133649 152917,305835,611669,1223339,2446677,4893355,9786709,19573419,
%U A133649 39146837,78293675,156587349,313174699,626349397,1252698795,2505397589,5010795179,10021590357,20043180715
%N A133649 A007318^(-1) * A133648.
%H A133649 Michael De Vlieger, <a href="/A133649/b133649.txt">Table of n, a(n) for n = 0..3320</a>
%H A133649 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,2).
%F A133649 Inverse binomial transform of A133648.
%F A133649 From _R. J. Mathar_, Dec 13 2008: (Start)
%F A133649 a(n) = A062092(n), n > 1.
%F A133649 G.f.: (1+2x)*(1+x+x^2)/((1-2x)*(1+x)). (End)
%e A133649 a(3) = (-1, 3, -3, 1) dot (1, 5, 18, 59) = (-1, 15, -54, 59), where A133648 = (1, 5, 18, 59, 184, 561, ...).
%t A133649 CoefficientList[Series[(1 + 2 x) (1 + x + x^2)/((1 - 2 x) (1 + x)), {x, 0, 33}], x] (* _Michael De Vlieger_, Mar 23 2022 *)
%Y A133649 Cf. A007318, A062092, A133648.
%K A133649 nonn
%O A133649 0,2
%A A133649 _Gary W. Adamson_, Sep 19 2007