A094537 A094536/2.

0, 0, 1, 2, 5, 10, 22, 44, 91, 182, 370, 740, 1490, 2980, 5980, 11960, 23957, 47914, 95902, 191804, 383750, 767500, 1535284, 3070568, 6141694, 12283388, 24567892, 49135784, 98273780, 196547560, 393099544, 786199088, 1572406987, 3144813974

Offset

0,4

Links

Table of n, a(n) for n=0..33.

Formula

Let b(0)=1; b(n)=2*b(n-1)-1/2*(1+(-1)^n)*b([n/2]); a(n)=2^(n-1)-b(n)/2 - Farideh Firoozbakht, Jun 10 2004

Mathematica

b[0]=1; b[n_]:=b[n]=2*b[n-1]-(1+(-1)^n)/2*b[Floor[n/2]]; a[n_]:=2^(n-1)-b[n]/2; Table[a[n], {n, 0, 35}]

Crossrefs

Cf. A003000, A094536.

Sequence in context: A026633 A093370 A372957 * A135098 A136488 A045621

Adjacent sequences: A094534 A094535 A094536 * A094538 A094539 A094540

Keyword

nonn,easy

Author

N. J. A. Sloane, Jun 06 2004

Extensions

More terms from Farideh Firoozbakht, Jun 10 2004

Status

approved