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 A281049 Number of n X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 0
 0, 1, 68, 1022, 7803, 46610, 221212, 926077, 3549039, 12749511, 43675963, 144504080, 466130380 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Diagonal of A281056. LINKS EXAMPLE Some solutions for n=4 ..0..1..0..0. .0..1..1..0. .0..1..1..0. .0..1..1..0. .0..1..0..1 ..0..1..1..0. .0..0..1..0. .0..0..1..1. .0..1..1..0. .0..1..0..1 ..0..0..0..0. .0..1..1..0. .1..0..1..0. .1..0..1..1. .1..0..1..0 ..1..0..1..1. .1..0..1..0. .0..0..1..1. .1..0..0..1. .1..1..1..0 CROSSREFS Cf. A281056. Sequence in context: A250338 A223374 A254645 * A264316 A251939 A163728 Adjacent sequences:  A281046 A281047 A281048 * A281050 A281051 A281052 KEYWORD nonn AUTHOR R. H. Hardin, Jan 13 2017 STATUS approved

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Last modified December 1 09:25 EST 2021. Contains 349426 sequences. (Running on oeis4.)