A099050 a(1)=1; for n>=2, a(n)=sum(1<=i<=j<=n-1, gcd(a(i),a(j))).

1, 1, 3, 8, 19, 42, 92, 194, 398, 808, 1638, 3334, 6686, 13392, 26842, 53708, 107450, 214952, 430148, 860340, 1720826, 3441688, 6883446, 13766950, 27533998, 55068040, 110136196, 220272460, 440545040, 881090532, 1762181454, 3524362990

Offset

1,3

Links

Table of n, a(n) for n=1..32.

Formula

a(n) is asymptotic to c*2^n where c=0.8205797305404015389561...

Crossrefs

Sequence in context: A095681 A079583 A357291 * A065352 A161993 A360489

Adjacent sequences: A099047 A099048 A099049 * A099051 A099052 A099053

Keyword

nonn

Author

Benoit Cloitre, Nov 13 2004

Status

approved