

A122981


Number of distributive sublattices of the lattice of ktuples less than the nth partition (in Abramowitz and Stegun order).


3



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

1,1


COMMENTS

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


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. A122978, A122982, A122979, A036036, A074139.
Sequence in context: A317305 A096998 A317307 * A122982 A101589 A061559
Adjacent sequences: A122978 A122979 A122980 * A122982 A122983 A122984


KEYWORD

more,nonn


AUTHOR

Franklin T. AdamsWatters, Sep 21 2006


STATUS

approved



