A200801 T(n,k) is the number of n X k 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

1, 2, 2, 5, 15, 5, 15, 178, 178, 15, 51, 2614, 9880, 2614, 51, 187, 40148, 583813, 583813, 40148, 187, 715, 622645, 34679839, 132636590, 34679839, 622645, 715, 2795, 9676364, 2060918000, 30147154218, 30147154218, 2060918000, 9676364, 2795

Offset

1,2

Links

Ron Hardin, Table of n, a(n) for n = 1..97

Example

Table starts:
.....1...........2.................5......................15
.....2..........15...............178....................2614
.....5.........178..............9880..................583813
....15........2614............583813...............132636590
....51.......40148..........34679839.............30147154218
...187......622645........2060918000...........6852264918471
...715.....9676364......122478253815........1557479347400065
..2795...150442627.....7278777317468......354005859128023982
.11051..2339207390...432571571252989....80463441477635545163
.43947.36372631268.25707362563355693.18288865135614195620421
...
Some solutions for n=5 and k=3:
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0
..2..0..0....0..1..1....0..0..2....2..2..0....2..2..0....2..2..0....2..1..2
..2..3..3....1..0..2....3..1..0....1..1..1....3..2..2....0..0..1....0..1..3
..2..2..0....3..2..1....3..3..0....2..2..1....3..1..3....1..1..1....1..1..2

Crossrefs

Main diagonal is A200794.

Columns 1..7 are A007581(n-1), A200795, A200796, A200797, A200798, A200799, A200780.

Cf. A199655, A198528.

Sequence in context: A291573 A208353 A208001 * A241119 A208408 A198528

Adjacent sequences: A200798 A200799 A200800 * A200802 A200803 A200804

Keyword

nonn,tabl

Author

R. H. Hardin, Nov 22 2011

Status

approved