A208857 Number of n X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward or left-upward diagonal neighbors.
1, 11, 5796, 44452082, 4071491223248, 4445765748006060562, 57867813487534623493632032, 8978812485595759770697498996138448
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..0..0....0..0..1..0....0..0..0..1....0..0..0..1....0..1..1..2 ..2..2..1..2....2..1..2..2....1..1..1..2....0..1..1..0....0..1..0..0 ..1..1..3..2....1..3..0..0....2..2..2..0....0..1..2..3....0..1..3..1 ..0..3..0..0....1..3..2..2....0..3..0..1....3..0..3..1....1..2..2..0
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