0,1

The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.

G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2

Partial sums of A005882.

Cf. A038588.

Sequence in context: A119104 A102253 A081513 this_sequence A090553 A078502 A107974

Adjacent sequences: A038584 A038585 A038586 this_sequence A038588 A038589 A038590

nonn

N. J. A. Sloane (njas(AT)research.att.com).