A018198 Possible numbers of complements of topologies on 7 points.

1, 6, 25, 32, 63, 64, 81, 128

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: A046416 A042879 A042495 * A079606 A372750 A184852

Adjacent sequences: A018195 A018196 A018197 * A018199 A018200 A018201

Keyword

nonn,more

Author

N. J. A. Sloane

Status

approved