A089262 a(n) = 2^floor(log_2(n)) - 2^floor(log_2(n*2/3)).

0, 0, 1, 0, 2, 2, 0, 0, 4, 4, 4, 4, 0, 0, 0, 0, 8, 8, 8, 8, 8, 8, 8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32

Offset

0,5

Links

Table of n, a(n) for n=0..79.

Formula

a(2n) = 2*a(n) + [n==1], a(2n+1) = 2*a(n).

G.f.: 1/(1-x) * Sum_{k>=0} 2^k*(t^2 - t^3) where t = x^(2^k).

Prog

(PARI) a(n)=if(n<1, 0, if(n%2==0, 2*a(n/2)+(n/2==1), 2*a((n-1)/2)))
(PARI) a(n)=2^floor(log(n)/log(2))-2^floor(log(n*2/3)/log(2))

Crossrefs

Cf. A053644.

Sequence in context: A268584 A119332 A335683 * A325788 A240509 A344901

Adjacent sequences: A089259 A089260 A089261 * A089263 A089264 A089265

Keyword

nonn,easy

Author

Ralf Stephan, Oct 30 2003

Status

approved