A241227 Number of scalene triangles on a centered hexagonal grid of size n.

0, 12, 648, 6084, 30444, 107376, 302916, 732024, 1576728, 3111012, 5724852, 9952620, 16509336, 26321160, 40567872, 60724104, 88605480, 126413772, 176788476, 242874756, 328359624, 437553360

Offset

1,2

Comments

A centered hexagonal grid of size n is a grid with A003215(n-1) points forming a hexagonal lattice.

Links

Table of n, a(n) for n=1..22.

Eric Weisstein's World of Mathematics, Hex Number.

Eric Weisstein's World of Mathematics, Scalene Triangle.

Formula

a(n) = A241223(n) - A241228(n).

Crossrefs

Cf. A190312.

Sequence in context: A013587 A126159 A220992 * A268549 A071307 A195574

Adjacent sequences: A241224 A241225 A241226 * A241228 A241229 A241230

Keyword

nonn,more

Author

Martin Renner, Apr 17 2014

Extensions

a(7) from Martin Renner, May 31 2014

a(8)-a(22) from Giovanni Resta, May 31 2014

Status

approved