A209381 1/4 the number of (n+1) X 8 0..2 arrays with every 2 X 2 subblock having distinct edge sums.

256, 882, 1792, 8612, 18176, 114056, 242176, 1784720, 3777536, 30197792, 63711232, 528982592, 1113952256, 9408350336, 19793944576, 168456608000, 354255650816, 3025121034752, 6360407375872, 54395601462272, 114358131163136

Offset

1,1

Comments

Column 7 of A209382.

Links

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

Formula

Empirical: a(n) = 32*a(n-2) - 308*a(n-4) + 1072*a(n-6) - 1152*a(n-8).

Empirical g.f.: 2*x*(128 + 441*x - 3200*x^2 - 9806*x^3 + 19840*x^4 + 55064*x^5 - 30976*x^6 - 79040*x^7) / ((1 - 2*x)*(1 + 2*x)*(1 - 2*x^2)*(1 - 8*x^2)*(1 - 18*x^2)). - Colin Barker, Jul 10 2018

Example

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

Crossrefs

Cf. A209382.

Sequence in context: A188248 A253822 A258733 * A236987 A236980 A224975

Adjacent sequences: A209378 A209379 A209380 * A209382 A209383 A209384

Keyword

nonn

Author

R. H. Hardin, Mar 07 2012

Status

approved