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 A210831 Number of (n+1) X (n+1) 0..3 symmetric matrices with every 2 X 2 subblock having two or three distinct values, and new values 0..3 introduced in lower triangle row major order. 0
 4, 141, 25169, 16941289, 40820607681, 350983455561087, 10767951776455515799, 1178739099906082214413048, 460405515303453536692441783335, 641654973151502496777935760164666385 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..10. EXAMPLE Some solutions for n=3 ..0..1..2..3....0..1..1..1....0..1..2..1....0..0..1..0....0..1..2..2 ..1..1..3..1....1..2..2..3....1..2..2..2....0..1..2..1....1..1..3..3 ..2..3..0..0....1..2..0..3....2..2..1..0....1..2..2..3....2..3..3..0 ..3..1..0..3....1..3..3..0....1..2..0..2....0..1..3..2....2..3..0..3 CROSSREFS Sequence in context: A262653 A299061 A299722 * A247483 A293752 A299833 Adjacent sequences: A210828 A210829 A210830 * A210832 A210833 A210834 KEYWORD nonn AUTHOR R. H. Hardin, Mar 27 2012 STATUS approved

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Last modified June 7 02:46 EDT 2023. Contains 363151 sequences. (Running on oeis4.)