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A203649 1/25 the number of (n+1)X(n+1) 0..4 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements 0
9, 1517, 1116249, 3906948333, 67213191427593, 5796397762880763341 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Diagonal of A203656

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for n=4

..0..1..2..2..4....0..2..2..0..0....1..1..4..3..2....3..3..0..3..4

..2..0..1..2..2....4..0..2..2..0....2..1..1..4..3....2..3..3..4..1

..3..2..0..1..2....3..4..0..2..2....0..2..1..1..4....3..3..0..3..4

..1..3..2..0..1....0..3..4..0..2....0..0..2..1..1....3..2..3..2..3

..0..1..3..2..0....3..0..3..4..0....3..0..0..2..1....4..3..0..3..0

CROSSREFS

Sequence in context: A231191 A217267 A300594 * A187131 A167774 A197206

Adjacent sequences:  A203646 A203647 A203648 * A203650 A203651 A203652

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 04 2012

STATUS

approved

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Last modified April 18 22:43 EDT 2021. Contains 343097 sequences. (Running on oeis4.)