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A227098 Number of n X n 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X(n+1) binary array having a sum of two, with rows and columns of the latter in lexicographically nondecreasing order 0
2, 15, 239, 8427, 754758, 180409504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Diagonal of A227103

LINKS

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

EXAMPLE

Some solutions for n=4

..0..0..1..1....0..1..0..0....0..0..0..0....0..1..1..0....0..0..1..0

..0..1..0..0....1..0..1..0....0..0..0..1....1..1..0..1....0..0..0..0

..1..1..1..0....1..0..0..1....1..0..1..0....1..1..0..0....1..0..0..1

..1..1..0..0....1..0..0..1....1..0..0..0....0..0..1..1....1..1..0..1

CROSSREFS

Sequence in context: A302358 A192561 A356587 * A180610 A156750 A292798

Adjacent sequences: A227095 A227096 A227097 * A227099 A227100 A227101

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 01 2013

STATUS

approved

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Last modified March 21 13:27 EDT 2023. Contains 361402 sequences. (Running on oeis4.)