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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 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: A212370 A302358 A192561 * 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 December 5 10:11 EST 2021. Contains 349543 sequences. (Running on oeis4.)