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A213693 Half the number of (n+1)X(n+1) symmetric 0..4 arrays with no 2X2 subblock summing to 8 0
56, 5470, 2322599, 4286833981, 34389632236877, 1199143411128185584, 181744271406372884215557, 119728593804039164010819562504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A213697

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A009600 A278777 A202565 * A180372 A255960 A201240

Adjacent sequences:  A213690 A213691 A213692 * A213694 A213695 A213696

KEYWORD

nonn

AUTHOR

R. H. Hardin Jun 18 2012

STATUS

approved

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Last modified August 8 18:58 EDT 2022. Contains 356016 sequences. (Running on oeis4.)