1,1

Entries are repeated if there is more than one matching b.

Table of n, a(n) for n=1..46.

Lorenz Halbeisen, Fans and bundles in the graph of pairwise sums and products, El. J. Comb. 11 (2004) #R6.

Sequence in context: A082668 A231044 A231076 * A043132 A039309 A043912

Adjacent sequences: A158516 A158517 A158518 * A158520 A158521 A158522

nonn

R. J. Mathar, Mar 20 2009

approved