A292102 Irregular triangle read by rows: T(n,k) (n >= 3) is the cardinality of the subsemilattice S(n,k) of the Bipartition lattice Bip(n).

24, 21, 158, 142, 1320, 1202, 1198, 13348, 12304, 12246

Offset

3,1

Links

Table of n, a(n) for n=3..12.

L. Santocanale, F. Wehrung, G. Grätzer, F. Wehrung, Generalizations of the Permutohedron, in Grätzer G., Wehrung F. (eds) Lattice Theory: Special Topics and Applications. Birkhäuser, Cham, pp. 287-397.

Example

card S(3, 0) = 24 ; card S(3, 1) = 21 .
card S(4, 0) = 158 ; card S(4, 1) = 142 .
card S(5, 0) = 1,320 ; card S(5, 1) = 1,202 ; card S(5, 2) = 1,198 .
card S(6, 0) = 13,348 ; card S(6, 1) = 12,304 ; card S(6, 2) = 12,246 .

Crossrefs

Sequence in context: A357971 A128560 A230340 * A022980 A023466 A278656

Adjacent sequences: A292099 A292100 A292101 * A292103 A292104 A292105

Keyword

nonn,tabf,more

Author

N. J. A. Sloane, Sep 13 2017

Status

approved