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 A210922 Number of n X n 0..3 symmetric matrices with every element equal to one or two horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order 0
 0, 1, 2, 49, 3312, 818235, 488196032, 845278581938, 3889846475035188, 49699973559580684560 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Table of n, a(n) for n=1..10. EXAMPLE Some solutions for n=4 ..0..0..1..1....0..0..1..0....0..0..1..1....0..0..2..2....0..0..1..0 ..0..0..2..0....0..1..1..0....0..0..1..1....0..1..1..1....0..0..1..0 ..1..2..2..0....1..1..2..2....1..1..2..2....2..1..0..0....1..1..1..0 ..1..0..0..0....0..0..2..2....1..1..2..2....2..1..0..0....0..0..0..0 CROSSREFS Sequence in context: A001568 A221134 A243720 * A257742 A269839 A088067 Adjacent sequences: A210919 A210920 A210921 * A210923 A210924 A210925 KEYWORD nonn AUTHOR R. H. Hardin Mar 29 2012 STATUS approved

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Last modified June 4 09:19 EDT 2023. Contains 363121 sequences. (Running on oeis4.)