A130819 2*k appears 2*k-1 times.

2, 4, 4, 4, 6, 6, 6, 6, 6, 8, 8, 8, 8, 8, 8, 8, 10, 10, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18

Offset: 1

Author

Paul Curtz, Jul 17 2007

Keywords

• nonn

Comments

The run-length encoding of this sequence is A000027 as it has one 2, three 4's, five 6's, and so on. - Alexander Fraebel, Sep 10 2012

Crossrefs

Equals twice A003059. - Michel Marcus, Sep 14 2020

Cf. A000027.

Formula

Sum_{n>=1} (-1)^(n+1)/a(n) = log(2)/2. - Amiram Eldar, Oct 01 2022