A192843 - OEIS

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A192843

Number of n X n symmetric 0..4 arrays with each element equal to at least two horizontal or vertical neighbors, containing at least one 4 and with new values 0..4 introduced in lower triangular row major order

0, 0, 0, 0, 0, 21, 1640, 407889, 76204819, 26261341398, 12631545191076

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

OFFSET

1,6

LINKS

Table of n, a(n) for n=1..11.

EXAMPLE

Some solutions for 6X6

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

..1..1..2..2..4..4....1..1..2..2..4..4....1..1..2..2..3..3....0..0..1..1..3..3

..3..3..4..4..3..3....3..3..4..4..1..1....3..3..3..3..4..4....2..2..3..3..4..4

CROSSREFS