A122979 Number of distributive sublattices of the lattice of k-tuples less than the n-th partition (in Abramowitz and Stegun 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, 1238, 2520, 5591, ?, ?, ?, ?, ?, 128.

Links

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

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

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, A122980, A122981, A036036, A074139.

Sequence in context: A013056 A013131 A293759 * A122980 A012985 A291178

Adjacent sequences: A122976 A122977 A122978 * A122980 A122981 A122982

Keyword

nonn,more

Author

Franklin T. Adams-Watters, Sep 21 2006

Status

approved