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 A137505 #20 Jan 02 2024 08:59:24
%S A137505 1,1,0,2,0,0,4,-4,4,4,-12,20,-12,-12,52,-76,52,52,-204,308,-204,-204,
%T A137505 820,-1228,820,820,-3276,4916,-3276,-3276,13108,-19660,13108,13108,
%U A137505 -52428,78644,-52428,-52428,209716,-314572,209716,209716,-838860,1258292,-838860,-838860,3355444,-5033164,3355444
%N A137505 Inverse binomial transform of A007910.
%H A137505 Harvey P. Dale, <a href="/A137505/b137505.txt">Table of n, a(n) for n = 0..1000</a>
%H A137505 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (-1,0,2).
%F A137505 Recurrence: a(n) = -a(n-1) + 2a(n-3), starting 1,1,0.
%F A137505 O.g.f.: (1+x)^2/((1-x)(1+2x+2x^2)). - _R. J. Mathar_, Jun 12 2008
%F A137505 a(4n) = a(4n+1) = (-1)^n*A109499(n). - Paul Curtz, Nov 01 2009
%F A137505 a(n) = (1/5) * (A137429(n-1) + 4) = A077973(n-2) + 2*A077973(n-1) + A077973(n). - _Ralf Stephan_, Aug 18 2013
%t A137505 LinearRecurrence[{-1,0,2},{1,1,0},50] (* _Harvey P. Dale_, Sep 17 2012 *)
%K A137505 sign
%O A137505 0,4
%A A137505 _Paul Curtz_, Apr 23 2008
%E A137505 More terms from _R. J. Mathar_, Jun 12 2008