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 A132863 #19 Jan 26 2020 21:03:23
%S A132863 1,3,21,195,2085,24243,297909,3806883,50082885,673851795,9229863381,
%T A132863 128273819523,1804331883621,25639360102515,367507859864565,
%U A132863 5307403512554595,77150495031376005,1127965980470739795,16575672566809158165,244695925293076974915
%N A132863 Expansion of 1/(1-3x*c(4x)), where c(x) is the g.f. of A000108.
%H A132863 Harvey P. Dale, <a href="/A132863/b132863.txt">Table of n, a(n) for n = 0..830</a>
%F A132863 a(n) = Sum_{k=0..n} A039599(n,k)*(-1)^k*4^(n-k). - _Philippe Deléham_, Dec 11 2007
%F A132863 From _Gary W. Adamson_, Jul 13 2011: (Start)
%F A132863 a(n) = upper left term in M^n, M = an infinite square production matrix as follows:
%F A132863 3, 3, 0, 0, 0, 0, ...
%F A132863 4, 4, 4, 0, 0, 0, ...
%F A132863 4, 4, 4, 4, 0, 0, ...
%F A132863 4, 4, 4, 4, 4, 0, ...
%F A132863 4, 4, 4, 4, 4, 4, ...
%F A132863 ... (End)
%F A132863 G.f.: 8/(5 + 3*sqrt(1-16x)). - _Philippe Deléham_, Oct 27 2011
%t A132863 CoefficientList[Series[8/(5+3Sqrt[1-16x]),{x,0,30}],x] (* _Harvey P. Dale_, Mar 09 2013 *)
%K A132863 nonn
%O A132863 0,2
%A A132863 _Philippe Deléham_, Nov 18 2007
%E A132863 More terms from _Philippe Deléham_, Oct 27 2011
%E A132863 Corrected by _Harvey P. Dale_, Mar 09 2013