This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A186808 #5 Mar 30 2012 18:40:58
%S A186808 4,5,6,10,12,13,18,21,23,26
%N A186808 Numbers n such that there are a prime number of unlabeled distributive lattices with n elements.
%C A186808 A lattice which satisfies the identities:
%C A186808 (x^y)V(x^z) = x^(yVz);
%C A186808 (xVy)^(xVz) = xV(y^z)
%C A186808 is said to be distributive.
%D A186808 Gratzer, G. Lattice Theory: First Concepts and Distributive Lattices. San Francisco, CA: W. H. Freeman, pp. 35-36, 1971.
%F A186808 {k: A006982(k) is in A000040}.
%e A186808 a(10) = 26 because there are 711811 unlabeled distributive lattices with 26 elements, and 711811 is a prime number.
%Y A186808 Cf. A000040, A006982
%K A186808 nonn
%O A186808 1,1
%A A186808 _Jonathan Vos Post_, Feb 26 2011