A209548 1/4 the number of (n+1)X4 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences

61, 562, 5075, 46515, 425803, 3901194, 35741496, 327471411, 3000373035, 27490276714, 251873944521, 2307743577771, 21144231048767, 193729722925588, 1775009260945536, 16263162106133544, 149007922275551448

Offset

1,1

Comments

Column 3 of A209553

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -59*a(n-2) +27*a(n-3) +267*a(n-4) -488*a(n-5) +111*a(n-6) +312*a(n-7) -174*a(n-8) -30*a(n-9) +18*a(n-10) +2*a(n-11)

Example

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

Crossrefs

Sequence in context: A302531 A061002 A303412 * A302898 A234926 A355602

Adjacent sequences: A209545 A209546 A209547 * A209549 A209550 A209551

Keyword

nonn

Author

R. H. Hardin Mar 10 2012

Status

approved