A194992 Number of lower triangles of an n X n 0..2 array with each element differing from all of its horizontal and vertical neighbors by one.

3, 6, 20, 80, 576, 4608, 69632, 1114112, 34603008, 1107296256, 69793218560, 4466765987840, 567347999932416, 72620543991349248, 18518801667747479552, 4740813226943354765312, 2422574005712127994626048

Offset

1,1

Comments

Column 2 of A194998.

Links

R. H. Hardin, Table of n, a(n) for n = 1..89

Example

Some solutions for 4 X 4
..2........1........0........2........0........0........0........0
..1.0......2.1......1.2......1.0......1.0......1.0......1.0......1.0
..2.1.2....1.2.1....0.1.0....2.1.2....2.1.0....0.1.0....2.1.0....2.1.0
..1.0.1.0..2.1.2.1..1.2.1.0..1.2.1.0..1.2.1.2..1.0.1.2..1.2.1.0..1.0.1.2

Crossrefs

Cf. A194998.

Sequence in context: A123559 A334329 A162171 * A163881 A238474 A019017

Adjacent sequences: A194989 A194990 A194991 * A194993 A194994 A194995

Keyword

nonn

Author

R. H. Hardin, Sep 07 2011

Status

approved