A220430 T(n,k)=Equals two maps: number of nXk binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and vertical neighbors in a random 0..3 nXk array

1, 1, 1, 2, 6, 2, 4, 23, 23, 4, 7, 94, 236, 94, 7, 12, 380, 2103, 2103, 380, 12, 21, 1494, 18366, 40412, 18366, 1494, 21, 37, 5939, 155250, 735555, 735555, 155250, 5939, 37, 65, 23398, 1286012, 12702453, 26927902, 12702453, 1286012, 23398, 65, 114, 92317

Offset

1,4

Comments

Table starts

..1.....1.......2........4........7.......12........21.......37....65.114

..1.....6......23.......94......380.....1494......5939....23398.92317

..2....23.....236.....2103....18366...155250...1286012.10530541

..4....94....2103....40412...735555.12702453.213282872

..7...380...18366...735555.26927902

.12..1494..155250.12702453

.21..5939.1286012

.37.23398

.65

Links

R. H. Hardin, Table of n, a(n) for n = 1..49

Example

Some solutions for n=3 k=4
..1..1..0..0....1..0..0..0....1..0..1..0....1..0..0..0....1..1..1..0
..0..0..1..0....1..0..0..1....1..0..0..0....1..0..1..0....0..0..0..0
..0..1..0..0....1..0..1..1....0..1..1..0....0..0..0..1....0..1..1..1

Crossrefs

Column 1 is A005251(n+1)

Column 2 is A220372

Sequence in context: A085193 A220242 A220375 * A220279 A221188 A220532

Adjacent sequences: A220427 A220428 A220429 * A220431 A220432 A220433

Keyword

nonn,tabl

Author

R. H. Hardin Dec 14 2012

Status

approved