A028492 Number of similarity classes of triangles which can be drawn using the lattice points in an n X n grid for vertices.

0, 1, 6, 20, 55, 119, 229, 402, 667, 1019, 1536, 2216, 3049, 4168, 5546, 7203, 9278, 11755, 14597, 18054, 22138, 26625, 31958, 38120, 44821, 52764, 61663, 71204, 82250, 94479, 107680, 122740, 139224, 156699, 176450, 198176, 220883

Offset

0,3

Links

Gismo Pracht, Table of n, a(n) for n = 0..112

Sean A. Irvine, Java program (github)

matheplanet.de, Python program

David J. Rusin, Lattice Problem (Triangles) [Broken link]

David J. Rusin, Lattice Problem (Triangles) [Cached copy]

Crossrefs

Cf. A028419.

Sequence in context: A038091 A027993 A396927 * A059822 A213589 A152959

Adjacent sequences: A028489 A028490 A028491 * A028493 A028494 A028495

Keyword

nonn

Author

David J. Rusin

Extensions

Extended by Ray Chandler, May 03 2011

Status

approved