A220279 T(n,k)=Equals two maps: number of nXk binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, vertical and antidiagonal neighbors in a random 0..1 nXk array

1, 1, 1, 2, 6, 2, 4, 25, 25, 4, 7, 87, 148, 87, 7, 12, 322, 1142, 1142, 322, 12, 21, 1168, 7987, 14111, 7987, 1168, 21, 37, 4303, 55034, 192553, 192553, 55034, 4303, 37, 65, 15680, 383153, 2539218, 4761666, 2539218, 383153, 15680, 65, 114, 57251, 2657666

Offset

1,4

Comments

Table starts

...1.....1.......2........4.........7........12.......21........37.......65

...1.....6......25.......87.......322......1168.....4303.....15680....57251

...2....25.....148.....1142......7987.....55034...383153...2657666.18466741

...4....87....1142....14111....192553...2539218.33491982.441269929

...7...322....7987...192553...4761666.120451866

..12..1168...55034..2539218.120451866

..21..4303..383153.33491982

..37.15680.2657666

..65.57251

.114

Links

R. H. Hardin, Table of n, a(n) for n = 1..59

Example

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

Crossrefs

Column 1 is A005251(n+1)

Sequence in context: A220242 A220375 A220430 * A221188 A220532 A060295

Adjacent sequences: A220276 A220277 A220278 * A220280 A220281 A220282

Keyword

nonn,tabl

Author

R. H. Hardin Dec 09 2012

Status

approved