cp's OEIS Frontend

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.

A271078 Number of non-isomorphic atomic lattices on n nodes.

This page as a plain text file.
%I A271078 #20 Feb 26 2020 07:15:34
%S A271078 0,1,1,0,1,1,2,4,9,22,59,181
%N A271078 Number of non-isomorphic atomic lattices on n nodes.
%o A271078 (SageMath)
%o A271078 for i in range(0, 12):
%o A271078     n = 0
%o A271078     for P in Posets(i):
%o A271078         if P.is_lattice():
%o A271078             L = LatticePoset(P)
%o A271078             if L.is_atomic():
%o A271078                 n += 1
%o A271078     print(n)
%Y A271078 Cf. A006966.
%K A271078 nonn,hard,more
%O A271078 0,7
%A A271078 _Jori Mäntysalo_, Mar 30 2016