A209380 1/4 the number of (n+1)X7 0..2 arrays with every 2X2 subblock having distinct edge sums

128, 410, 840, 4004, 8648, 52784, 114056, 790712, 1693448, 12487208, 26563080, 201742280, 427484168, 3292956296, 6963468296, 54006743816, 114088980488, 887752094216, 1874426109960, 14608478297096, 30837161410568

Offset

1,1

Comments

Column 6 of A209382

Links

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

Formula

Empirical: a(n) = a(n-1) +38*a(n-2) -38*a(n-3) -516*a(n-4) +516*a(n-5) +3144*a(n-6) -3144*a(n-7) -8480*a(n-8) +8480*a(n-9) +7936*a(n-10) -7936*a(n-11)

Example

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

Crossrefs

Sequence in context: A220582 A203449 A195090 * A135271 A369638 A223316

Adjacent sequences: A209377 A209378 A209379 * A209381 A209382 A209383

Keyword

nonn

Author

R. H. Hardin Mar 07 2012

Status

approved