%I A006355
%S A006355 1,0,2,2,4,6,10,16,26,42,68,110,178,288,466,754,1220,1974,3194,5168,
%T A006355 8362,13530,21892,35422,57314,92736,150050,242786,392836,635622,1028458,
%U A006355 1664080,2692538,4356618,7049156,11405774,18454930,29860704,48315634
%N A006355 Number of binary vectors of length n containing no singletons.
%C A006355 Number of cvtemplates at n-2 letters given <= 2 consecutive consonants 
               or vowels (n >= 4).
%C A006355 Number of (n,2) Freiman-Wyner sequences.
%C A006355 Diagonal sums of the Riordan array ((1-x+x^2)/(1-x), x/(1-x)), A072405 
               (where this begins 1,0,1,1,1,1,...). - Paul Barry (pbarry(AT)wit.ie), 
               May 04 2005
%C A006355 a(n) = A119457(n-1,n-2) for n>2. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               May 20 2006
%D A006355 I. F. Blake, The enumeration of certain run length sequences, Information 
               and Control, 55 (1982), 222-237.
%D A006355 Enoch Haga, Room for Expansion, Word Ways, 33 (No. 2, 2000), pp. 106-113 
               (see p. 110).
%D A006355 A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of 
               combinatorial proof, M.A.A. 2003, id. 16,51.
%H A006355 <a href="Sindx_Rea.html#recLCC">Index entries for sequences related to 
               linear recurrences with constant coefficients</a>
%H A006355 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=898">
               Encyclopedia of Combinatorial Structures 898</a>
%F A006355 a(n+2) = F(n-1) + F(n+2), for n>0.
%F A006355 G.f.: (1-x+x^2)/(1-x-x^2) - Paul Barry (pbarry(AT)wit.ie), May 04 2005
%p A006355 a := n-> if n=0 then 1 else (Matrix([[2,-2]]). Matrix([[1,1], [1,0]])^n)[1,
               1] fi; seq (a(n), n=0..38); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), 
               Aug 18 2008]
%t A006355 lst={1};Do[AppendTo[lst,Fibonacci[n+3]-Fibonacci[n]],{n,-1,4*4!}];lst 
               [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 11 2009]
%t A006355 lst={1};a=2;s=3;Do[a=s-(a+1);AppendTo[lst,a];s+=a,{n,5!}];lst [From Vladimir 
               Orlovsky (4vladimir(AT)gmail.com), Oct 27 2009]
%Y A006355 Except for initial term, = 2*Fibonacci numbers (A000045).
%Y A006355 Essentially the same as A055389.
%Y A006355 Cf. A097925, A097926.
%Y A006355 Essentially the same as A047992, A068922, A054886 and A090991.
%Y A006355 Sequence in context: A139582 A034410 A050194 this_sequence A055389 A163733 
               A084202
%Y A006355 Adjacent sequences: A006352 A006353 A006354 this_sequence A006356 A006357 
               A006358
%K A006355 nonn,easy,nice
%O A006355 0,3
%A A006355 David M. Bloom.
%E A006355 More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               May 20 2006
%E A006355 Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 31 2006