A084432 G.f.: 2/(1-x) + sum(k>=0, t^2(3-t)/(1+t)/(1-t)^2, t=x^2^k).

2, 5, 4, 10, 6, 11, 8, 19, 10, 17, 12, 24, 14, 23, 16, 36, 18, 29, 20, 38, 22, 35, 24, 49, 26, 41, 28, 52, 30, 47, 32, 69, 34, 53, 36, 66, 38, 59, 40, 79, 42, 65, 44, 80, 46, 71, 48, 98, 50, 77, 52, 94, 54, 83, 56, 109, 58, 89, 60, 108, 62, 95, 64, 134, 66, 101

Offset

1,1

Links

Table of n, a(n) for n=1..66.

Formula

a(1)=2, a(2n) = a(n)+2n+1, a(2n+1) = 2n+2.

Dirichlet g.f.: 2^s/(2^s-1) * (zeta(s)+zeta(s-1)) - Ralf Stephan, Jun 17 2007

Prog

(PARI) for(n=1, 100, l=ceil(log(n)/log(2)); t=polcoeff(sum(k=0, l, 1/(1-x^2^k)^2) + O(x^(n+1)), n); print1(t", "))

Crossrefs

Cf. A069895.

Sequence in context: A324142 A339809 A360896 * A071297 A356875 A114393

Adjacent sequences: A084429 A084430 A084431 * A084433 A084434 A084435

Keyword

nonn,easy

Author

Ralf Stephan, Jun 27 2003

Status

approved