A283517 Number of nX3 0..1 arrays with no 1 equal to more than three of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements.

0, 1, 20, 270, 2763, 26662, 241796, 2115564, 18020972, 150431216, 1235860816, 10022560088, 80412418752, 639331124272, 5043680344120, 39521427506168, 307850445104320, 2385411084242780, 18397022091700304, 141285768645661084

Offset

1,3

Comments

Column 3 of A283522.

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -36*a(n-2) -235*a(n-3) +171*a(n-4) +2481*a(n-5) +5734*a(n-6) +6894*a(n-7) +5364*a(n-8) +3397*a(n-9) +1947*a(n-10) +846*a(n-11) +277*a(n-12) +126*a(n-13) +12*a(n-14) +8*a(n-15) for n>19

Example

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

Crossrefs

Cf. A283522.

Sequence in context: A125455 A019928 A025934 * A180799 A021594 A224248

Adjacent sequences: A283514 A283515 A283516 * A283518 A283519 A283520

Keyword

nonn

Author

R. H. Hardin, Mar 09 2017

Status

approved