A122980 Number of distributive sublattices of the lattice of k-tuples less than the n-th partition (in Mathematica order), that include the maximum element.

2, 4, 7, 8, 21, 45, 16, 58, 84, 200, 500, 32, 152, 293, 748, 1184, 3220

Offset

1,1

Comments

After a(18) - for partition [1^5] - the sequence continues ?, 64, 384, 938, 2520, 1238, 5591, ?, ?, ?, ?, ?, 128.

Links

Table of n, a(n) for n=1..17.

Example

For a(5), partition [2,1], the lattice consists of the 6 pairs (i,j) where 0<=i<=2 and 0<=j<=1, with (i,j) <= (i',j') iff i<=i' and j<=j'. {(2,1), (2,0), (0,1), (0,0)} is one distributive sublattice.

Crossrefs

Cf. A122977, A122979, A122982, A080577, A074139.

Sequence in context: A013131 A293759 A122979 * A012985 A291178 A023145

Adjacent sequences: A122977 A122978 A122979 * A122981 A122982 A122983

Keyword

nonn,more

Author

Franklin T. Adams-Watters, Sep 21 2006

Status

approved