1,3

Any such graph consists of a single connected Euler graph (see A003049) plus a number of isolated vertices.

Max Alekseyev, Table of n, a(n) for n = 1..60

a(n) = Sum_{k=1..n} A003049(k).

A variant of A002854. See also A003049.

Sequence in context: A034731 A216435 A110888 * A058698 A058699 A250193

Adjacent sequences: A133733 A133734 A133735 * A133737 A133738 A133739

nonn

N. J. A. Sloane, based on email from Max Alekseyev, Jan 28 2010

Edited and extended by Max Alekseyev, Jan 28 2010

approved