A122982 Number of distributive sublattices of the lattice of k-tuples less than the n-th partition (in Mathematica order).

3, 7, 12, 15, 37, 73, 31, 103, 146, 319, 731, 63, 271, 505, 1191, 1833, 4618

Offset

1,1

Comments

After a(18) - for partition [1^5] - the sequence continues ?, 127, 687, 1611, 4031, 2102, 8589, ?, ?, ?, ?, ?, 255.

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. A122978, A122981, A122980, A080577, A074139.

Sequence in context: A317307 A331042 A122981 * A101589 A061559 A165990

Adjacent sequences: A122979 A122980 A122981 * A122983 A122984 A122985

Keyword

more,nonn

Author

Franklin T. Adams-Watters, Sep 21 2006

Status

approved