1,5

Table of n, a(n) for n=1..11.

Keith M. Briggs, Combinatorial Graph Theory

A diagonal of triangle in A126736.

Sequence in context: A048861 A053972 A204561 * A259610 A109074 A227020

Adjacent sequences: A126735 A126736 A126737 * A126739 A126740 A126741

nonn

N. J. A. Sloane, Feb 16 2007

a(11) from Michael Sollami, Jan 29 2012.

approved