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 A152264 #18 Feb 07 2023 17:57:20
%S A152264 1,9,87,891,9513,104409,1165887,13155291,149353713,1701720009,
%T A152264 19429431687,222100769691,2540606477913,29073358875609,
%U A152264 332774973917487,3809447614844091,43611934023382113,499306241307571209
%N A152264 a(n) = ((9+sqrt(6))^n + (9-sqrt(6))^n)/2.
%C A152264 Binomial transform of A152263. - _Philippe Deléham_, Dec 03 2008
%H A152264 Harvey P. Dale, <a href="/A152264/b152264.txt">Table of n, a(n) for n = 0..944</a>
%H A152264 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (18, -75).
%F A152264 From _Philippe Deléham_, Dec 03 2008: (Start)
%F A152264 a(n) = 18*a(n-1) - 75*a(n-2), n > 1; a(0)=1, a(1)=9.
%F A152264 G.f.: (1-9*x)/(1-18*x+75*x^2).
%F A152264 a(n) = Sum_{k=0..n} A098158(n,k)*9^(2k-n)*6^(n-k). (End)
%t A152264 CoefficientList[Series[(1-9x)/(1-18x+75x^2),{x,0,20}],x] (* or *) LinearRecurrence[{18,-75},{1,9},20] (* _Harvey P. Dale_, Feb 07 2023 *)
%o A152264 (Magma) Z<x>:= PolynomialRing(Integers()); N<r6>:=NumberField(x^2-6); S:=[ ((9+r6)^n+(9-r6)^n)/2: n in [0..17] ]; [ Integers()!S[j]: j in [1..#S] ]; // _Klaus Brockhaus_, Dec 03 2008
%K A152264 nonn
%O A152264 0,2
%A A152264 Al Hakanson (hawkuu(AT)gmail.com), Dec 01 2008
%E A152264 Extended beyond a(6) by _Klaus Brockhaus_, Dec 03 2008