1,6
Table of n, a(n) for n=1..11.
Keith M. Briggs, Combinatorial Graph Theory
A diagonal of triangle in A126744.
Sequence in context: A264123 A304645 A233313 * A107668 A214400 A197989
Adjacent sequences: A126744 A126745 A126746 * A126748 A126749 A126750
nonn,hard,more
N. J. A. Sloane, Feb 18 2007
a(11) from Michael Sollami, Jan 29 2012
approved