A205239 Number of (n+1)X2 0..2 arrays with the number of rightwards and downwards edge increases in each 2X2 subblock differing from the number in each of its horizontal and vertical neighbors.

81, 486, 2990, 18148, 111041, 677732, 4143102, 25302238, 154597952, 944323666, 5769147079, 35241970176, 215294819906, 1315202262082, 8034520991634, 49082022117918, 299838801088734, 1831687968517910, 11189641429502614

Offset

1,1

Comments

Column 1 of A205246

Links

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

Formula

Empirical: a(n) = 27*a(n-2) +48*a(n-3) +35*a(n-4) +258*a(n-5) +400*a(n-6) +502*a(n-7) +1956*a(n-8) +2498*a(n-9) +333*a(n-10) +544*a(n-11) +2005*a(n-12) +980*a(n-13) -5963*a(n-14) -556*a(n-15) +1856*a(n-16) +2430*a(n-17) -2045*a(n-18) -2184*a(n-19) -4376*a(n-20) -1720*a(n-21) -448*a(n-22) -64*a(n-23) for n>24

Example

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

Crossrefs

Sequence in context: A237077 A236646 A205246 * A236427 A235842 A235838

Adjacent sequences: A205236 A205237 A205238 * A205240 A205241 A205242

Keyword

nonn

Author

R. H. Hardin, Jan 24 2012

Status

approved