A266062 Number of nX2 integer arrays with each element equal to the number of horizontal, vertical, diagonal and antidiagonal neighbors exactly one smaller than itself.

3, 17, 35, 89, 323, 1057, 3027, 9257, 29835, 92561, 288027, 898873, 2818275, 8824849, 27652507, 86466761, 270984643, 849833089, 2661782123, 8337922937, 26141124755, 81934791281, 256731280891, 804699050537, 2522377797859, 7905371708193

Offset

1,1

Comments

Column 2 of A266067.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +20*a(n-3) +30*a(n-4) -50*a(n-5) -160*a(n-6) -512*a(n-7) -404*a(n-8) +948*a(n-9) +1880*a(n-10) +4248*a(n-11) +1088*a(n-12) -3776*a(n-13) -7488*a(n-14) -5376*a(n-15) +4352*a(n-16) +4608*a(n-17) +8192*a(n-18)

Example

Some solutions for n=4
..0..1....0..1....0..0....2..2....1..0....0..0....1..0....1..0....1..2....0..1
..2..1....2..2....0..0....1..1....1..1....2..2....2..2....1..1....1..0....2..1
..2..2....1..0....0..2....1..0....1..1....1..1....1..0....1..1....2..2....2..2
..1..0....1..2....1..1....1..2....1..0....1..0....1..1....0..1....1..0....0..1

Crossrefs

Cf. A266067.

Sequence in context: A146021 A146133 A297735 * A031290 A152908 A031386

Adjacent sequences: A266059 A266060 A266061 * A266063 A266064 A266065

Keyword

nonn

Author

R. H. Hardin, Dec 20 2015

Status

approved