1,1
CRC Handbook of Combinatorial Designs, 1996, p. 418.
Sequence in context: A145195 A096022 A097222 * A110978 A087719 A174216
Adjacent sequences: A004066 A004067 A004068 * A004070 A004071 A004072
nonn,hard
N. J. A. Sloane (njas(AT)research.att.com).