4,2
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Earl Glen Whitehead, Jr., Four-discordant permutations, J. Austral. Math. Soc. Ser. A 28 (1979), no. 3, 369-377.
Sequence in context: A155633 A002493 A054364 * A052664 A090373 A041184
Adjacent sequences: A004306 A004307 A004308 * A004310 A004311 A004312
nonn
N. J. A. Sloane (njas(AT)research.att.com).
