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 A123013 #10 Jul 12 2021 02:41:03
%S A123013 1,0,-253,-1288,191521,1629320,-141854525,-1729034384,103325091969,
%T A123013 1676517701264,-73862084838333,-1537330036703384,51664189190888737,
%U A123013 1355829753195189272,-35196896202269431421,-1160994902209537876768,23182613727557891170817,970833262148740191853344
%N A123013 a(n) = A122192(n)/6.
%H A123013 G. C. Greubel, <a href="/A123013/b123013.txt">Table of n, a(n) for n = 0..500</a>
%H A123013 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,-759,-2576,-759,0,-1).
%F A123013 G.f.: (1 + 506*x^2 + 1288*x^3 + 253*x^4)/(1 + 759*x^2 + 2576*x^3 + 759*x^4 + x^6). - _G. C. Greubel_, Jul 11 2021
%t A123013 LinearRecurrence[{0,-759,-2576,-759,0,-1}, {1,0,-253,-1288,191521,1629320}, 31] (* _G. C. Greubel_, Jul 11 2021 *)
%o A123013 (Sage)
%o A123013 def A123013_list(prec):
%o A123013 P.<x> = PowerSeriesRing(ZZ, prec)
%o A123013 return P( (1+506*x^2+1288*x^3+253*x^4)/(1+759*x^2+2576*x^3+759*x^4 +x^6) ).list()
%o A123013 A123013_list(30) # _G. C. Greubel_, Jul 11 2021
%Y A123013 Cf. A122192.
%K A123013 sign
%O A123013 0,3
%A A123013 _N. J. A. Sloane_, Nov 12 2006