A046905 Posets with n points with property that there is no nonsingelton proper subset T for which x not in T implies x<T or x>T or x incomparable with every element of T.

1, 1, 0, 0, 24, 360, 17400, 1066800

Offset

0,5

References

J. A. Wright, There are 718 6-point topologies, quasi-orderings and transgraphs, Notices Amer. Math. Soc., 17 (1970), p. 646, Abstract #70T-A106.

Links

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

J. A. Wright, Letter to N. J. A. Sloane, Apr 06 1972, listing 18 sequences

Index entries for sequences related to posets

Crossrefs

A subset of the posets enumerated in A003431. Cf. A046904.

Sequence in context: A081144 A126780 A052741 * A028115 A125481 A028074

Adjacent sequences: A046902 A046903 A046904 * A046906 A046907 A046908

Keyword

nonn

Author

John A. Wright.

Status

approved