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%I A006984 M2298 #25 Sep 19 2023 05:01:22
%S A006984 1,1,3,4,3,4,7,7,9,7,7,12,13,12,13,16,13,13,19,16,21,19,19,21,25,21,
%T A006984 27,28,21,27,31,28,27,28,31,36,37,31,39,37,37,36,43,39,39,39,39,48,49,
%U A006984 43,43
%N A006984 Greatest minimal norm of sublattice of index n in hexagonal lattice.
%C A006984 The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.
%D A006984 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006984 Andrey Zabolotskiy, <a href="/A006984/b006984.txt">Table of n, a(n) for n = 1..500</a>
%H A006984 M. Bernstein, N. J. A. Sloane and P. E. Wright, On Sublattices of the Hexagonal Lattice, Discrete Math. 170 (1997) 29-39 (<a href="http://neilsloane.com/doc/paul.txt">Abstract</a>, <a href="http://neilsloane.com/doc/paul.pdf">pdf</a>, <a href="http://neilsloane.com/doc/paul.ps">ps</a>).
%H A006984 G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a>.
%H A006984 N. J. A. Sloane, <a href="/A006984/a006984.pdf">Computer printout with notes, Mar. 1994</a>.
%Y A006984 Cf. A003051, A003050, A001615.
%K A006984 nonn,nice
%O A006984 1,3
%A A006984 _N. J. A. Sloane_, _Mira Bernstein_

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