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A252856 Number of (n+2) X (3+2) 0..2 arrays with every consecutive three elements in every row, column, diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order. 1
684, 738, 1197, 1962, 3582, 6795, 12762, 24552, 47367, 91440, 176940, 342711, 663624, 1285704, 2490993, 4826304, 9351324, 18119295, 35108028, 68026230, 131809365, 255397428, 494865270, 958865463, 1857925458, 3599971020 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - a(n-5) + a(n-6) - 2*a(n-7) + a(n-8) for n>10.

Empirical g.f.: 9*x*(76 - 70*x - 31*x^2 - 48*x^3 - 38*x^4 + 35*x^5 - 86*x^6 + 95*x^7 - 20*x^8 - 2*x^9) / ((1 - x)*(1 + x + x^2)*(1 - 2*x + x^3 - 2*x^4 + x^5)). - Colin Barker, Dec 07 2018

EXAMPLE

Some solutions for n=4:

..0..1..1..2..2....0..1..0..0..2....0..1..1..0..0....0..1..0..1..0

..2..1..2..1..2....2..0..0..1..1....0..1..0..1..1....1..2..2..1..1

..0..0..1..1..0....2..1..2..1..1....2..2..1..1..0....0..2..0..2..0

..2..0..2..0..2....1..1..2..2..0....2..2..0..0..1....1..1..2..2..0

..0..2..2..0..0....2..2..1..1..0....1..0..1..0..0....0..1..0..0..2

..0..2..0..2..0....1..2..1..2..1....2..0..0..1..1....1..2..2..0..0

CROSSREFS

Column 3 of A252861.

Sequence in context: A076574 A015386 A245393 * A184089 A254071 A022050

Adjacent sequences:  A252853 A252854 A252855 * A252857 A252858 A252859

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 23 2014

STATUS

approved

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Last modified May 7 18:29 EDT 2021. Contains 343652 sequences. (Running on oeis4.)