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