A253463 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally, vertically, diagonally and antidiagonally.

540, 800, 1400, 3072, 8536, 15888, 44464, 94416, 273808, 562320, 1622320, 3376272, 9768496, 20246928, 58535344, 121496976, 351356848, 728945040, 2107845040, 4373737872, 12647655856, 26242285968, 75884757424, 157453992336

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-2) + 8*a(n-4) - 12*a(n-6) for n>7.

Empirical g.f.: 4*x*(135 + 200*x - 325*x^2 - 232*x^3 - 696*x^4 - 1468*x^5 - 734*x^6) / ((1 - x)*(1 + x)*(1 + 2*x^2)*(1 - 6*x^2)). - Colin Barker, Dec 14 2018

Example

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

Crossrefs

Column 2 of A253468.

Sequence in context: A289221 A345390 A261290 * A255105 A298685 A185463

Adjacent sequences: A253460 A253461 A253462 * A253464 A253465 A253466

Keyword

nonn

Author

R. H. Hardin, Jan 01 2015

Status

approved