A241225 Number of right triangles on a centered hexagonal grid of size n.

0, 12, 216, 1104, 3708, 9396, 20304, 38868, 68364, 112632, 176076, 263832, 381924, 536424, 735240, 985896, 1296540, 1676508, 2137392, 2689248, 3344244, 4114020

Offset: 1

Author

Martin Renner, Apr 17 2014

Keywords

• nonn

Comments

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

Links

• Eric Weisstein's World of Mathematics, Hex Number.
• Eric Weisstein's World of Mathematics, Right Triangle.

Crossrefs

Cf. A077435.

Formula

a(n) = A241223(n) - A241224(n) - A241226(n).

Extensions

a(7) from Martin Renner, May 31 2014

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