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The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.
I. Jensen, Table of n, a(n) for n = 0..60 (from link below)
I. Jensen, More terms
G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2
Sequence in context: A264769 A169765 A169768 * A099306 A228630 A174647
Adjacent sequences: A057383 A057384 A057385 * A057387 A057388 A057389
N. J. A. Sloane, Aug 30 2000