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 A166157 #11 May 02 2016 00:24:33
%S A166157 1,-8,80,-656,6416,-53648,515600,-4378256,41501456,-356735888,
%T A166157 3344840720,-29029824656,269858356496,-2360005731728,21789807399440,
%U A166157 -191710220083856,1760576352843536,-15563712198881168
%N A166157 a(n) = (8^n+16*(-9)^n)/17.
%H A166157 G. C. Greubel, <a href="/A166157/b166157.txt">Table of n, a(n) for n = 0..1000</a>
%H A166157 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-1, 72).
%F A166157 a(n) = 72*a(n-2)-a(n-1), a(0)= 1, a(1)= -8, for n>1.
%F A166157 G.f.: (1-7x)/(1+x-72*x^2).
%F A166157 a(n)= Sum_{k, 0<=k<=n} A112555(n,k)*(-9)^k.
%F A166157 E.g.f.: (1/17)*(exp(8*x) + 16*exp(-9*x)). - _G. C. Greubel_, May 01 2016
%t A166157 LinearRecurrence[{-1,72},{1,-8},20] (* _Harvey P. Dale_, Jun 23 2012 *)
%o A166157 (PARI) a(n)=(8^n+16*(-9)^n)/17 \\ _Charles R Greathouse IV_, May 02 2016
%Y A166157 Cf. A166035, A166036, A166149, A166152, A166153.
%K A166157 easy,sign
%O A166157 0,2
%A A166157 _Philippe Deléham_, Oct 08 2009