A192842 - OEIS

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A192842

Number of n X n symmetric 0..3 arrays with each element equal to at least two horizontal or vertical neighbors, containing at least one 3 and with new values 0..3 introduced in lower triangular row major order

0, 0, 0, 0, 0, 145, 6944, 635377, 69009813, 12541320254, 3495358855982, 1626847265319815, 1240274531663638765

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,6

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for 6X6

..0..0..0..0..0..0....0..0..1..1..3..3....0..0..1..1..2..2....0..0..0..0..2..2

..0..0..1..1..0..0....0..0..1..1..3..3....0..0..1..1..2..2....0..0..0..0..2..2

..0..1..1..1..2..2....1..1..2..2..3..3....1..1..1..1..1..1....0..0..0..1..1..1

..0..1..1..2..2..2....1..1..2..2..3..3....1..1..1..1..1..1....0..0..1..1..1..1