1,3

Table of n, a(n) for n=1..5.

Cf. A088310.

Sequence in context: A266312 A181232 A275054 * A158042 A297049 A147860

Adjacent sequences: A088613 A088614 A088615 * A088617 A088618 A088619

nonn

Yuval Dekel and Vladeta Jovovic, Nov 17 2003

What if you also ask that the two main diagonals are also distinct? - N. J. A. Sloane, Jan 03 2004.

approved