A231020 Number of (n+3)X(2+3) 0..3 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, and upper left element zero

16, 242, 724, 10534, 28128, 419878, 1144652, 16946918, 46058744, 683352174, 1857863476, 27552792942, 74908095984, 1110991043910, 3020446141788, 44796988899478, 121789649054696, 1806294227298910, 4910772371719684

Offset

1,1

Comments

Column 2 of A231023

Links

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

Formula

Empirical: a(n) = 31*a(n-2) +375*a(n-4) +233*a(n-6) -7946*a(n-8) -884*a(n-10) -16296*a(n-12) -203520*a(n-14) +53120*a(n-16)

Example

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

Crossrefs

Sequence in context: A135518 A369393 A179092 * A274856 A064232 A074153

Adjacent sequences: A231017 A231018 A231019 * A231021 A231022 A231023

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved