A183328 T(n,k)=Number of nXk binary arrays with each 1 adjacent to exactly two other 1s

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 6, 10, 10, 6, 1, 1, 9, 19, 27, 19, 9, 1, 1, 13, 37, 72, 72, 37, 13, 1, 1, 19, 69, 179, 289, 179, 69, 19, 1, 1, 28, 129, 447, 996, 996, 447, 129, 28, 1, 1, 41, 244, 1139, 3325, 4740, 3325, 1139, 244, 41, 1, 1, 60, 460, 2912, 11415, 21259

Offset

1,5

Comments

Table starts

.1..1...1....1......1.......1........1.........1..........1...........1

.1..2...3....4......6.......9.......13........19.........28..........41

.1..3...6...10.....19......37.......69.......129........244.........460

.1..4..10...27.....72.....179......447......1139.......2912........7434

.1..6..19...72....289.....996.....3325.....11415......39720......138689

.1..9..37..179....996....4740....21259.....96524.....443793.....2054180

.1.13..69..447...3325...21259...128371....770542....4639132....28160294

.1.19.129.1139..11415...96524...770542...6115158...48449560...386449543

.1.28.244.2912..39720..443793..4639132..48449560..505971397..5319953708

.1.41.460.7434.138689.2054180.28160294.386449543.5319953708.73890230419

Links

R. H. Hardin, Table of n, a(n) for n = 1..391

Example

Some solutions for 7X6
..0..1..1..1..1..1....0..0..1..1..1..0....0..0..1..1..1..1....0..0..1..1..1..0
..0..1..0..0..0..1....0..1..1..0..1..0....1..1..1..0..0..1....0..0..1..0..1..0
..0..1..0..1..1..1....1..1..0..0..1..1....1..0..0..0..0..1....1..1..1..0..1..1
..0..1..0..1..0..0....1..0..0..0..0..1....1..1..0..0..0..1....1..0..0..0..0..1
..1..1..0..1..1..0....1..0..0..0..1..1....0..1..0..0..0..1....1..1..0..0..0..1
..1..0..0..0..1..0....1..0..1..1..1..0....0..1..1..1..0..1....0..1..1..0..0..1
..1..1..1..1..1..0....1..1..1..0..0..0....0..0..0..1..1..1....0..0..1..1..1..1

Crossrefs

Column 2 is A000930(n+1)

Sequence in context: A008571 A230860 A051137 * A034328 A034253 A203952

Adjacent sequences: A183325 A183326 A183327 * A183329 A183330 A183331

Keyword

nonn,tabl

Author

R. H. Hardin Jan 03 2011

Status

approved