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 A082685 #17 Oct 07 2015 18:11:38
%S A082685 1,4,18,86,422,2094,10438,52126,260502,1302254,6510758,32552766,
%T A082685 162761782,813804814,4069015878,20345063006,101725282262,508626345774,
%U A082685 2543131597798,12715657726846,63578288109942,317891439501134
%N A082685 (2*5^n + 2^n)/3.
%C A082685 Binomial transform of A007583
%C A082685 Row sums of A114195. - _Paul Barry_, Nov 16 2005
%H A082685 Vincenzo Librandi, <a href="/A082685/b082685.txt">Table of n, a(n) for n = 0..1000</a>
%H A082685 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (7,-10)
%F A082685 G.f.: (1-3x)/((1-5x)(1-2x))
%F A082685 a(n)=sum{k=0..n, sum{j=0..n, C(n, j)C(j+k, 2k)2^(j-k)}}. - _Paul Barry_, Nov 16 2005
%F A082685 a(0)=1, a(1)=4, a(n)=7*a(n-1)-10*a(n-2). - _Harvey P. Dale_, Apr 09 2014
%t A082685 Table[(2*5^n+2^n)/3,{n,0,30}] (* or *) LinearRecurrence[{7,-10},{1,4},30] (* _Harvey P. Dale_, Apr 09 2014 *)
%t A082685 CoefficientList[Series[(1 - 3 x)/((1 - 5 x) (1 - 2 x)), {x, 0, 50}], x] (* _Vincenzo Librandi_, Apr 10 2014 *)
%o A082685 (PARI) a(n)=(2*5^n+2^n)/3 \\ _Charles R Greathouse IV_, Oct 07 2015
%Y A082685 Cf. A001045.
%K A082685 easy,nonn
%O A082685 0,2
%A A082685 _Paul Barry_, Apr 11 2003