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 A133655 #19 Mar 23 2022 07:39:46
%S A133655 1,7,15,23,31,39,47,55,63,71,79,87,95,103,111,119,127,135,143,151,159,
%T A133655 167,175,183,191,199,207,215,223,231,239,247,255,263,271,279,287,295,
%U A133655 303,311,319,327,335,343,351,359,367,375,383,391,399,407,415
%N A133655 a(n) = 2*A016777(n) + A016777(n-1) - (n+1).
%H A133655 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A133655 Equals "1" followed by A004771.
%F A133655 Binomial transform of [1, 6, 2, -2, 2, -2, 2, ...].
%F A133655 G.f.: (2*x^2+5*x+1)/(x-1)^2. - _Harvey P. Dale_, Sep 13 2011
%e A133655 a(3) = 23 = 2*A016777(3) + A016777(2) - 4 = 2*10 + 7 - 4.
%e A133655 a(3) = 23 = (1, 3, 3, 1) dot (1, 6, 2, -2) = (1, 18, 6, -2).
%t A133655 CoefficientList[Series[(2 x^2+5 x+1)/(x-1)^2,{x,0,60}],x] (* _Harvey P. Dale_, Sep 13 2011 *)
%Y A133655 Cf. A004771, A016777.
%K A133655 nonn,easy
%O A133655 0,2
%A A133655 _Gary W. Adamson_, Sep 20 2007
%E A133655 More terms and corrected definition from _R. J. Mathar_, Jun 08 2008