A018195 Possible numbers of complements of topologies on 4 points.

1, 3, 4, 7, 12, 14, 15, 16

Offset

0,2

Links

Table of n, a(n) for n=0..7.

J. I. Brown and S. Watson, The number of complements of a topology on n points is at least 2^n (except for some special cases), Discr. Math., 154 (1996), 27-39.

Crossrefs

Sequence in context: A377600 A305185 A083561 * A086417 A051215 A192112

Adjacent sequences: A018192 A018193 A018194 * A018196 A018197 A018198

Keyword

nonn,more

Author

N. J. A. Sloane.

Status

approved