A234975 Number of (n+1) X (1+1) 0..4 arrays with every 2 X 2 subblock having the sum of the absolute values of the edge differences equal to 8.

182, 1664, 14420, 127982, 1127550, 9962574, 87941706, 776556490, 6856434758, 60540092874, 534541037814, 4719777004110, 41673602284166, 367960260263026, 3248932448319154, 28686692988827766, 253291301375224138

Offset

1,1

Links

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

Formula

Empirical: a(n) = 9*a(n-1) + 13*a(n-2) - 134*a(n-3) + a(n-4) + 480*a(n-5) - 224*a(n-6) - 96*a(n-7).

Empirical g.f.: 2*x*(91 + 13*x - 1461*x^2 + 479*x^3 + 5523*x^4 - 2943*x^5 - 1197*x^6) / (1 - 9*x - 13*x^2 + 134*x^3 - x^4 - 480*x^5 + 224*x^6 + 96*x^7). - Colin Barker, Oct 16 2018

Example

Some solutions for n=4:
..4..1....4..3....0..4....4..1....4..1....0..1....4..0....1..3....2..0....3..0
..4..0....1..4....0..4....2..3....0..0....1..4....0..0....2..0....2..4....4..0
..4..0....0..1....1..3....0..4....2..4....0..3....4..3....3..4....0..1....4..1
..3..0....1..4....3..1....1..3....0..4....4..4....2..0....3..0....4..1....4..0
..2..3....0..3....1..3....4..2....1..1....2..0....4..1....4..0....3..0....3..1

Crossrefs

Column 1 of A234982.

Sequence in context: A157205 A154067 A234982 * A186125 A209852 A321637

Adjacent sequences: A234972 A234973 A234974 * A234976 A234977 A234978

Keyword

nonn

Author

R. H. Hardin, Jan 02 2014

Status

approved