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 A099141 #26 Sep 05 2020 03:12:23
%S A099141 1,7,73,847,10033,119287,1419193,16886527,200931553,2390878567,
%T A099141 28449011113,338514191407,4027973401873,47928772841047,
%U A099141 570303484727833,6786029465163487,80746825394092993,960804818888214727
%N A099141 a(n) = 5^n * T(n,7/5) where T is the Chebyshev polynomial of the first kind.
%C A099141 In general, r^n * T(n,(r+2)/r) has g.f. (1-(r+2)*x)/(1-2*(r+2)*x + r^2*x^2), e.g.f. exp((r+2)*x)*cosh(2*sqrt(r+1)*x), a(n) = Sum_{k=0..n} (r+1)^k*binomial(2*n,2*k) and a(n) = (1+sqrt(r+1))^(2*n)/2 + (1-sqrt(r+1))^(2*n)/2.
%H A099141 Seiichi Manyama, <a href="/A099141/b099141.txt">Table of n, a(n) for n = 0..500</a>
%H A099141 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%H A099141 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (14,-25).
%F A099141 G.f.: (1-7*x)/(1-14*x+25*x^2);
%F A099141 e.g.f.: exp(7*x)*cosh(2*sqrt(6)*x);
%F A099141 a(n) = 5^n * T(n, 7/5) where T is the Chebyshev polynomial of the first kind;
%F A099141 a(n) = Sum_{k=0..n} 6^k * binomial(2n, 2k);
%F A099141 a(n) = (1+sqrt(6))^(2n)/2 + (1-sqrt(6))^(2n)/2.
%F A099141 a(0)=1, a(1)=7, a(n) = 14*a(n-1) - 25*a(n-2) for n > 1. - _Philippe Deléham_, Sep 08 2009
%t A099141 LinearRecurrence[{14,-25},{1,7},30] (* _Harvey P. Dale_, Dec 26 2014 *)
%Y A099141 Column k=6 of A333988.
%Y A099141 Cf. A081294, A001541, A090965, A083884, A099140, A099142.
%K A099141 easy,nonn
%O A099141 0,2
%A A099141 _Paul Barry_, Sep 30 2004