%I A022087
%S A022087 0,4,4,8,12,20,32,52,84,136,220,356,576,932,1508,2440,3948,
%T A022087 6388,10336,16724,27060,43784,70844,114628,185472,300100,
%U A022087 485572,785672,1271244,2056916,3328160,5385076,8713236
%N A022087 Fibonacci sequence beginning 0 4.
%D A022087 A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of 
               combinatorial proof, M.A.A. 2003, id. 18.
%H A022087 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A022087 a(n) = round( (8phi-4)/5 phi^n) (works for n>2) - Thomas Baruchel, Sep 
               08 2004
%F A022087 a(n) = 4F(n) = F(n-2) + F(n) + F(n+2), with F(n) = A000045(n).
%F A022087 a(n) = A119457(n+2,n-1) for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               May 20 2006
%F A022087 G.f.: 4x/(1-x-x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), 
               Nov 19 2008]
%p A022087 a := n-> (Matrix([[4,0]]). Matrix([[1,1],[1,0]])^n)[1,2]: seq (a(n), 
               n=0..32); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 17 
               2008]
%t A022087 a={};b=0;c=4;AppendTo[a,b];AppendTo[a,c];Do[b=b+c;AppendTo[a,b];c=b+c;
               AppendTo[a,c],{n,1,9,1}];a (Vladimir Orlovsky, Jul 22 2008)
%Y A022087 Sequence in context: A086663 A003829 A002368 this_sequence A095294 A030168 
               A112435
%Y A022087 Adjacent sequences: A022084 A022085 A022086 this_sequence A022088 A022089 
               A022090
%K A022087 nonn
%O A022087 0,2
%A A022087 N. J. A. Sloane (njas(AT)research.att.com).