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A215843
Number of horizontal, vertical, diagonal and antidiagonal neighbor colorings of the even squares of an n X n array with new integer colors introduced in row major order.
0
1, 1, 4, 78, 159712, 1396243937, 3815473909467500, 45390943862783143279730, 397034361835031697465783534020014, 15507107984840512941104718700286316624403232, 879811362496064190233012463916172065914614436408327993774, 228191793894588365948208713657625336579386337610734511061398668053881111
OFFSET
1,3
COMMENTS
Diagonal of A215847.
EXAMPLE
Some solutions for n=4:
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..0....x..2..x..3....x..2..x..3....x..2..x..3....x..2..x..3
..3..x..4..x....1..x..4..x....1..x..0..x....4..x..0..x....4..x..0..x
..x..0..x..3....x..0..x..2....x..3..x..1....x..3..x..2....x..5..x..2
CROSSREFS
Sequence in context: A246606 A210903 A054951 * A374523 A048957 A006425
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 24 2012
EXTENSIONS
a(7)-a(12) from Andrew Howroyd, Jun 25 2017
STATUS
approved