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 A292296 #16 Sep 18 2017 08:04:00
%S A292296 0,0,0,6,30,114,402,1386,4746,16218,55386,189114,645690,2204538,
%T A292296 7526778,25698042,87738618,299558394,1022756346,3491908602,
%U A292296 11922121722,40704669690,138974435322,474488401914,1620004737018,5531042144250,18884159102970,64474552123386
%N A292296 Sum of values of vertices of type B at level n of the hyperbolic Pascal pyramid.
%H A292296 Colin Barker, <a href="/A292296/b292296.txt">Table of n, a(n) for n = 0..1000</a>
%H A292296 László Németh, <a href="http://arxiv.org/abs/1511.02067">Hyperbolic Pascal pyramid</a>, arXiv:1511.0267 [math.CO], 2015 (2nd line of Table 2).
%H A292296 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-6,2).
%F A292296 a(n) = 5*a(n-1) - 6*a(n-2) + 2*a(n-3), n >= 4.
%F A292296 From _Colin Barker_, Sep 17 2017: (Start)
%F A292296 G.f.: 6*x^3 / ((1 - x)*(1 - 4*x + 2*x^2)).
%F A292296 a(n) = (1/2)*(-12 + (9-6*sqrt(2))*(2+sqrt(2))^n + (2-sqrt(2))^n*(9+6*sqrt(2))) for n>0.
%F A292296 (End)
%t A292296 CoefficientList[Series[6*x^3/((1 - x)*(1 - 4*x + 2*x^2)), {x, 0, 30}],
%t A292296 x] (* _Wesley Ivan Hurt_, Sep 17 2017 *)
%o A292296 (PARI) concat(vector(3), Vec(6*x^3 / ((1 - x)*(1 - 4*x + 2*x^2)) + O(x^30))) \\ _Colin Barker_, Sep 17 2017
%Y A292296 Cf. A264237.
%K A292296 nonn,easy
%O A292296 0,4
%A A292296 _Eric M. Schmidt_, Sep 14 2017