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 A210925 Number of n X n 0..3 symmetric matrices with every element equal to zero, two or three horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order 0
 1, 3, 39, 2212, 314852, 110451021, 95121973827, 200885189935045, 1039262747697700932, 13162671799070468638683 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..10. EXAMPLE Some solutions for n=4 ..0..1..2..3....0..1..2..3....0..1..0..1....0..1..0..3....0..1..2..1 ..1..0..1..2....1..0..1..0....1..2..1..3....1..0..2..1....1..2..3..0 ..2..1..3..3....2..1..0..2....0..1..2..1....0..2..1..3....2..3..2..3 ..3..2..3..3....3..0..2..1....1..3..1..2....3..1..3..0....1..0..3..1 CROSSREFS Sequence in context: A015017 A210921 A290516 * A300046 A267624 A342178 Adjacent sequences: A210922 A210923 A210924 * A210926 A210927 A210928 KEYWORD nonn AUTHOR R. H. Hardin Mar 29 2012 STATUS approved

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Last modified June 1 03:55 EDT 2023. Contains 363068 sequences. (Running on oeis4.)