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 A124746 #13 Aug 27 2024 09:16:27
%S A124746 1,0,1,0,1,-1,1,-1,1,-2,2,-2,2,-3,4,-4,4,-5,7,-8,8,-9,12,-15,16,-17,
%T A124746 21,-27,31,-33,38,-48,58,-64,71,-86,106,-122,135,-157,192,-228,257,
%U A124746 -292,349,-420,485,-549,641,-769,905,-1034,1190,-1410,1674,-1939,2224,-2600
%N A124746 Expansion of (1+x^2)/(1-x^4+x^5).
%H A124746 Paolo Xausa, <a href="/A124746/b124746.txt">Table of n, a(n) for n = 0..1000</a>
%H A124746 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1,-1).
%F A124746 a(n) = Sum_{k=0..floor(n/2)} C(floor(k/2),n-2k)*(-1)^n.
%F A124746 a(n) = (-1)^n*A124789(n). - _R. J. Mathar_, Jun 30 2020
%t A124746 LinearRecurrence[{0, 0, 0, 1, -1}, {1, 0, 1, 0, 1}, 100] (* _Paolo Xausa_, Aug 27 2024 *)
%Y A124746 Diagonal sums of A124744.
%Y A124746 Cf. A124789.
%K A124746 easy,sign
%O A124746 0,10
%A A124746 _Paul Barry_, Nov 06 2006