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 A166977 #12 Oct 31 2018 16:15:35
%S A166977 0,1,5,7,17,31,65,127,257,511,1025,2047,4097,8191,16385,32767,65537,
%T A166977 131071,262145,524287,1048577,2097151,4194305,8388607,16777217,
%U A166977 33554431,67108865,134217727,268435457,536870911,1073741825,2147483647
%N A166977 Jacobsthal-Lucas numbers A014551, except a(0) = 0.
%C A166977 The sequence (-1)^n*a(n) is the inverse binomial transform of A166956.
%C A166977 The main diagonal of the table of a(n) and its higher differences in successive rows is 0,4,8,16,32,.. , 4*A131577(n).
%H A166977 G. C. Greubel, <a href="/A166977/b166977.txt">Table of n, a(n) for n = 0..1000</a>
%H A166977 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,2).
%F A166977 a(n) = A014551(n), n>0.
%F A166977 a(n) - A001045(n) = A097073(n), n>0.
%F A166977 a(n) - A001045(n) = 4*A001045(n-1).
%F A166977 a(n) = a(n-1) + 2*a(n-2), n>2.
%F A166977 G.f.: x*(1 + 4*x)/((1+x) * (1-2*x)).
%F A166977 a(n) = (-1)^n + 2^n for n>0. - _Colin Barker_, Jun 06 2012
%F A166977 E.g.f.: exp(2*x) + exp(-x) - 2. - _G. C. Greubel_, May 30 2016
%t A166977 Join[{0, 1}, LinearRecurrence[{1, 2}, {5, 7}, 50]] (* or *) Table[2^n + (-1)^n, {n,1,25}] (* _G. C. Greubel_, May 30 2016 *)
%K A166977 nonn,less,easy
%O A166977 0,3
%A A166977 _Paul Curtz_, Oct 26 2009
%E A166977 Edited and extended by _R. J. Mathar_, Mar 14 2010