The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A084566 a(0)=1, a(2n) = 2a(2n-1)+a(n), a(2n+1) = 2a(2n)+2a(n). 0

%I #2 Mar 30 2012 18:41:20

%S 1,4,12,32,76,176,384,832,1740,3632,7440,15232,30848,62464,125760,

%T 253184,508108,1019696,2043024,4093312,8194064,16403008,32821248,

%U 65672960,131376768,262815232,525692928,1051510784,2103147328

%N a(0)=1, a(2n) = 2a(2n-1)+a(n), a(2n+1) = 2a(2n)+2a(n).

%C a(n) ~ 2^(n+e) with e = 2.9701632052178...

%F G.f. prod(k>=0, (1+2x^2^k)/(1-2x^2^k)).

%o (PARI) a(n)=if(n<1,n<1,if(n%2==0,2*a(n-1)+a(n/2),2*a(n-1)+2*a((n-1)/2)))

%Y Cf. A018819.

%K nonn,easy

%O 0,2

%A _Ralf Stephan_, Jun 28 2003

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 11 23:02 EDT 2024. Contains 375842 sequences. (Running on oeis4.)