A185825 T(n,k)=1/5 the number of nXk 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

0, 1, 1, 1, 9, 1, 5, 76, 76, 5, 9, 656, 1584, 656, 9, 29, 5680, 49036, 49036, 5680, 29, 65, 49248, 1266624, 4443292, 1266624, 49248, 65, 181, 426928, 35446376, 378212944, 378212944, 35446376, 426928, 181, 441, 3701360, 956312244, 32995092992

Offset

1,5

Comments

Table starts

....0........1...........1.............5..............9.............29

....1........9..........76...........656...........5680..........49248

....1.......76........1584.........49036........1266624.......35446376

....5......656.......49036.......4443292......378212944....32995092992

....9.....5680.....1266624.....378212944...100480040192.28043363244452

...29....49248....35446376...32995092992.28043363244452

...65...426928...956312244.2852526229300

..181..3701360.26231137608

..441.32089696

.1165

Links

R. H. Hardin, Table of n, a(n) for n = 1..60

Example

Some solutions for 5X4 with a(1,1)=0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..1..1..1..0....0..1..1..0....1..1..1..0....1..1..1..0....0..1..1..0
..3..0..3..0....4..2..2..0....2..3..0..0....2..2..2..0....4..1..2..0
..3..0..3..0....4..0..2..1....2..3..0..2....0..0..4..4....4..0..2..4
..3..2..2..2....0..0..2..1....3..3..0..2....4..4..2..2....4..0..2..4

Crossrefs

Column 1 is A006131(n-2)

Sequence in context: A271856 A164802 A201888 * A198879 A161321 A090656

Adjacent sequences: A185822 A185823 A185824 * A185826 A185827 A185828

Keyword

nonn,tabl

Author

R. H. Hardin Feb 05 2011

Status

approved