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A186808
Numbers n such that there are a prime number of unlabeled distributive lattices with n elements.
0
4, 5, 6, 10, 12, 13, 18, 21, 23, 26
OFFSET
1,1
COMMENTS
A lattice which satisfies the identities:
(x^y)V(x^z) = x^(yVz);
(xVy)^(xVz) = xV(y^z)
is said to be distributive.
REFERENCES
Gratzer, G. Lattice Theory: First Concepts and Distributive Lattices. San Francisco, CA: W. H. Freeman, pp. 35-36, 1971.
FORMULA
{k: A006982(k) is in A000040}.
EXAMPLE
a(10) = 26 because there are 711811 unlabeled distributive lattices with 26 elements, and 711811 is a prime number.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Feb 26 2011
STATUS
approved