A234927 Number of (n+2) X (1+2) 0..2 arrays with each 3 X 3 subblock having the sum of its 72 absolute element differences equal to 34 and no adjacent elements equal.

56, 88, 138, 176, 312, 432, 584, 960, 1408, 1872, 3168, 4544, 6080, 10176, 14720, 19648, 33024, 47616, 63616, 106752, 154112, 205824, 345600, 498688, 666112, 1118208, 1613824, 2155520, 3618816, 5222400, 6975488, 11710464, 16900096

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-3) + 4*a(n-6) for n>9.

Empirical g.f.: 2*x*(28 + 44*x + 69*x^2 + 32*x^3 + 68*x^4 + 78*x^5 + 4*x^6 - 8*x^7 - 4*x^8) / (1 - 2*x^3 - 4*x^6). - Colin Barker, Oct 16 2018

Example

Some solutions for n=5:
..0..2..1....0..1..2....1..2..0....0..1..2....1..2..0....0..2..1....2..0..2
..2..1..2....1..2..1....2..0..1....1..2..0....2..0..2....2..1..2....1..2..1
..1..2..0....2..0..2....0..1..0....2..1..2....1..2..1....1..2..0....2..0..2
..2..0..1....1..2..0....1..0..2....0..2..1....2..0..2....2..0..2....1..2..0
..0..1..0....2..1..2....0..2..1....1..0..2....1..2..0....1..2..1....2..1..2
..1..0..2....0..2..1....2..1..2....0..1..0....2..1..2....2..0..2....1..2..0
..0..2..0....1..0..2....0..2..1....1..0..2....0..2..1....1..2..0....0..1..2

Crossrefs

Sequence in context: A214250 A286981 A254369 * A104394 A353281 A101935

Adjacent sequences: A234924 A234925 A234926 * A234928 A234929 A234930

Keyword

nonn

Author

R. H. Hardin, Jan 01 2014

Status

approved