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 A228568 #15 Mar 06 2020 13:45:12 %S A228568 2,8,48,320,2176,14848,101376,692224,4726784,32276480,220397568, %T A228568 1504968704,10276569088,70172803072,479169871872,3271976550400, %U A228568 22342453428224,152563815022592,1041770892754944,7113656621858816,48575085832830976,331691433687777280 %N A228568 a(n) = 2^n*A056236(n). %C A228568 Bhadouria et al. call this the 2-binomial transform of the 2-Lucas numbers. %H A228568 Colin Barker, <a href="/A228568/b228568.txt">Table of n, a(n) for n = 0..1000</a> %H A228568 P. Bhadouria, D. Jhala, B. Singh, <a href="http://dx.doi.org/10.22436/jmcs.08.01.07">Binomial Transforms of the k-Lucas Sequences and its Properties</a>, The Journal of Mathematics and Computer Science (JMCS), Volume 8, Issue 1, Pages 81-92; sequence T_2. %H A228568 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,-8). %F A228568 G.f.: 2*( 1-4*x ) / ( 1-8*x+8*x^2 ). %F A228568 a(n) = 2*A084130(n). %F A228568 From _Colin Barker_, Mar 16 2016: (Start) %F A228568 a(n) = ((4-2*sqrt(2))^n+(2*(2+sqrt(2)))^n). %F A228568 a(n) = 8*a(n-1)-8*a(n-2) for n>1. %F A228568 (End) %o A228568 (PARI) Vec(2*(1-4*x)/(1-8*x+8*x^2) + O(x^50)) \\ _Colin Barker_, Mar 16 2016 %K A228568 nonn,easy %O A228568 0,1 %A A228568 _R. J. Mathar_, Nov 10 2013