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 A077830 #10 Nov 05 2021 15:35:56
%S A077830 1,3,11,42,157,588,2204,8259,30949,115977,434606,1628619,6103000,
%T A077830 22870056,85702025,321155187,1203479779,4509855786,16899992477,
%U A077830 63330128340,237319937332,889320046107,3332590398005,12488371098225,46798254229006,175369276077483
%N A077830 Expansion of 1/(1-3*x-2*x^2-3*x^3).
%H A077830 Harvey P. Dale, <a href="/A077830/b077830.txt">Table of n, a(n) for n = 0..1000</a>
%H A077830 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,2,3).
%t A077830 CoefficientList[Series[1/(1-3x-2x^2-3x^3),{x,0,40}],x] (* or *) LinearRecurrence[{3,2,3},{1,3,11},40] (* _Harvey P. Dale_, Nov 05 2021 *)
%Y A077830 Partial sums of S(n, x), for x=1...15, A021823, A000217, A027941, A061278, A089817, A053142, A092521, A076765, A092420, A097784, A097826-A097828, A076139, A097829.
%K A077830 nonn
%O A077830 0,2
%A A077830 _N. J. A. Sloane_, Nov 17 2002