3,2

Table of n, a(n) for n=3..19.

a(5) = 2 since when U(5) = {1,2,3,4} acts naturally on the five 4-subsets {0,1,2,3}, {0,1,2,4}, {0,1,3,4}, {0,2,3,4}, {1,2,3,4} of Z/(5) the orbits are {{0,1,2,3},{0,1,2,4}, {0,1,3,4}, {0,2,3,4}} and {{1,2,3,4}}.

Cf. A063379, A065957, A000005, A056376 + 1, A056371 - 1

Sequence in context: A245287 A254595 A137453 * A019078 A205384 A199181

Adjacent sequences: A063378 A063379 A063380 * A063382 A063383 A063384

nonn

W. Edwin Clark, Jul 15 2001

approved