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 A122981 Number of distributive sublattices of the lattice of k-tuples less than the n-th partition (in Abramowitz and Stegun order). 3

%I

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

%N Number of distributive sublattices of the lattice of k-tuples less than the n-th partition (in Abramowitz and Stegun order).

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

%H M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

%e 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.

%Y Cf. A122978, A122982, A122979, A036036, A074139.

%K more,nonn

%O 1,1

%A _Franklin T. Adams-Watters_, Sep 21 2006

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Last modified May 13 23:41 EDT 2021. Contains 343868 sequences. (Running on oeis4.)