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 A001808 #31 Apr 21 2025 10:47:49
%S A001808 1,11,67,297,1068,3300,9076,22748,52834,115126,237590,467842,884236,
%T A001808 1611908,2845492,4880668,8157227,13316953,21280337,33346963,51325352,
%U A001808 77699128,115837592,170260168,246965732,353839564,501152588,702169700,973886344,1337915096
%N A001808 Expansion of 1/((1+x)*(1-x)^12).
%H A001808 Vincenzo Librandi, <a href="/A001808/b001808.txt">Table of n, a(n) for n = 0..1000</a>
%H A001808 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (11,-54,154,-275,297,-132,-132,297,-275,154,-54,11,-1).
%t A001808 CoefficientList[Series[1/((1+x)(1-x)^12),{x,0,50}],x] (* _Vincenzo Librandi_, Feb 24 2012 *)
%t A001808 LinearRecurrence[{11,-54,154,-275,297,-132,-132,297,-275,154,-54,11,-1},{1,11,67,297,1068,3300,9076,22748,52834,115126,237590,467842,884236},30] (* _Harvey P. Dale_, Jun 22 2014 *)
%o A001808 (PARI) Vec(1/((1+x)*(1-x)^12)+O(x^20)) \\ _Edward Jiang_, Sep 07 2014
%o A001808 (Magma)
%o A001808 R<x>:=PowerSeriesRing(Integers(), 50);
%o A001808 Coefficients(R!( 1/((1+x)*(1-x)^12) )); // _G. C. Greubel_, Apr 20 2025
%o A001808 (SageMath)
%o A001808 def A001808_list(prec):
%o A001808 P.<x> = PowerSeriesRing(ZZ, prec)
%o A001808 return P( 1/((1+x)*(1-x)^12) ).list()
%o A001808 print(A001808_list(50)) # _G. C. Greubel_, Apr 20 2025
%Y A001808 Twelfth column of A112465.
%K A001808 nonn,easy
%O A001808 0,2
%A A001808 _N. J. A. Sloane_