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 A192995 Number of n X n symmetric 0..1 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..1 introduced in lower triangular row major order 1
 0, 1, 1, 5, 24, 184, 2052, 34481, 852317, 31436448, 1719054683, 139749375352, 16887682211105, 3032513808121101, 809442991768500676, 321179427812462958357, 189437827654558885755438 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS R. H. Hardin, Table of n, a(n) for n = 1..19 EXAMPLE Some solutions for 8X8 containing a 1 ..0..0..0..0..0..0..0..0....0..0..0..0..1..1..0..0....0..0..0..0..0..0..0..0 ..0..0..1..1..0..0..0..0....0..1..1..0..1..1..0..0....0..1..1..1..1..1..0..0 ..0..1..1..1..0..0..1..1....0..1..1..0..1..1..1..0....0..1..1..1..1..1..0..0 ..0..1..1..1..1..0..1..1....0..0..0..0..0..1..1..0....0..1..1..1..0..0..0..0 ..0..0..0..1..1..0..1..1....1..1..1..0..0..1..1..0....0..1..1..0..0..1..1..0 ..0..0..0..0..0..0..0..1....1..1..1..1..1..1..0..0....0..1..1..0..1..1..1..0 ..0..0..1..1..1..0..0..1....0..0..1..1..1..0..0..0....0..0..0..0..1..1..1..0 ..0..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0 CROSSREFS Sequence in context: A184597 A009601 A009676 * A027851 A120765 A259355 Adjacent sequences:  A192992 A192993 A192994 * A192996 A192997 A192998 KEYWORD nonn AUTHOR R. H. Hardin Jul 14 2011 STATUS approved

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Last modified May 10 22:11 EDT 2021. Contains 343780 sequences. (Running on oeis4.)