2,5
CRC Handbook of Combinatorial Designs, 1996, p. 480.
Sequence in context: A067866 A157198 A156954 * A043633 A171641 A204289
Adjacent sequences: A004075 A004076 A004077 * A004079 A004080 A004081
nonn,hard
N. J. A. Sloane (njas(AT)research.att.com).