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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. 3
2, 4, 7, 8, 21, 45, 16, 58, 84, 200, 500, 32, 152, 293, 748, 1184, 3220 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 19 21:57 EDT 2021. Contains 343117 sequences. (Running on oeis4.)