A193313 - OEIS

A193313

Number of n X n symmetric 0..7 arrays with no element equal to any horizontal or vertical neighbor, containing at least one 7 and with new values 0..7 introduced in lower triangular row major order

0, 0, 0, 384, 25487513, 3218172167526, 1689214255082226544, 4735679809903927663201085, 77891271754155746362358782867546

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OFFSET

1,4

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

Some solutions for 4X4

..0..1..3..6....0..1..2..5....0..1..3..5....0..1..3..6....0..1..3..5

..1..2..4..7....1..2..3..6....1..2..4..6....1..2..4..2....1..2..0..6

..3..4..5..1....2..3..4..7....3..4..5..7....3..4..5..4....3..0..4..7

..6..7..1..0....5..6..7..1....5..6..7..2....6..2..4..7....5..6..7..3

CROSSREFS

Sequence in context: A188783 A008692 A364181 * A067518 A071763 A254352

Adjacent sequences: A193310 A193311 A193312 * A193314 A193315 A193316

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 22 2011

STATUS

approved