A253462 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally, vertically, diagonally and antidiagonally.

81, 540, 3640, 24208, 162016, 1081504, 7227096, 48272160, 322493040, 2154281664, 14391427080, 96138251504, 642233318880, 4290297708128, 28660448653048, 191460012669504, 1279008408531440, 8544145042353728, 57077359575083624

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 27*a(n-2) + 30*a(n-3) - 7*a(n-4) - 8*a(n-5) - 75*a(n-6) - 48*a(n-7) - 16*a(n-8).

Empirical g.f.: x*(81 + 378*x + 373*x^2 - 82*x^3 - 313*x^4 - 916*x^5 - 709*x^6 - 156*x^7) / (1 - 2*x - 27*x^2 - 30*x^3 + 7*x^4 + 8*x^5 + 75*x^6 + 48*x^7 + 16*x^8). - Colin Barker, Dec 14 2018

Example

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

Crossrefs

Column 1 of A253468.

Sequence in context: A235565 A235560 A253468 * A206512 A235833 A235588

Adjacent sequences: A253459 A253460 A253461 * A253463 A253464 A253465

Keyword

nonn

Author

R. H. Hardin, Jan 01 2015

Status

approved