A220428 Equals two maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and vertical neighbors in a random 0..3 nX3 array

2, 23, 236, 2103, 18366, 155250, 1286012, 10530541, 85522873, 690893996, 5562055980, 44675368067, 358307397221, 2870920452221, 22988510045507, 184001223691193, 1472357876261742, 11779577116001434, 94231542167997828

Offset

1,1

Comments

Column 3 of A220430

Links

R. H. Hardin, Table of n, a(n) for n = 1..24

Example

Some solutions for n=3
..1..0..0....0..1..1....0..1..1....1..1..1....0..0..1....1..1..1....1..0..0
..0..1..0....0..0..1....1..1..1....1..0..0....0..1..1....0..0..1....0..1..0
..0..1..0....0..1..1....0..0..0....1..0..0....1..1..0....0..0..0....0..0..1

Crossrefs

Sequence in context: A048677 A132933 A220373 * A110773 A088087 A088085

Adjacent sequences: A220425 A220426 A220427 * A220429 A220430 A220431

Keyword

nonn

Author

R. H. Hardin Dec 14 2012

Status

approved