A010737 - OEIS

%I #11 Mar 30 2012 18:38:36

%S 4,6,9,13,19,27,39,55,79,111,159,223,319,447,639,895,1279,1791,2559,

%T 3583,5119,7167,10239,14335,20479,28671,40959,57343,81919,114687,

%U 163839,229375,327679,458751,655359

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

%F a(2n)=5*2^n-1 and a(2n+1)=7*2^n-1 or a(n)=(6-(-1)^n)*2^floor(n/2)-1 - _Benoit Cloitre_, May 04 2003

%p A010737 := proc(n) options remember; if n <= 1 then 2*n+4 else 2*A010737(n-2)+1; fi end;

%o (PARI) a(n)=(6-(-1)^n)*2^floor(n/2)-1

%K nonn,easy

%O 0,1

%A _N. J. A. Sloane_, Ulrich Hund (hund(AT)math.tu-berlin.de)