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 A192644 Number of n X n symmetric 0..7 arrays with each element equal to at least one horizontal or vertical neighbor and any new values 0..7 introduced in lower triangular row major order. 0
 0, 1, 5, 137, 17687, 14743487, 78148721677, 2854620794876552 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Table of n, a(n) for n=1..8. EXAMPLE Some solutions for 6 X 6 containing a 7: ..0..0..1..1..5..5....0..0..2..2..5..5....0..0..0..2..4..4....0..0..0..2..5..7 ..0..0..2..3..6..6....0..1..1..3..5..5....0..0..1..2..5..5....0..0..1..2..5..7 ..1..2..2..3..4..5....2..1..3..3..6..6....0..1..1..3..6..7....0..1..1..3..3..7 ..1..3..3..4..4..5....2..3..3..4..4..4....2..2..3..3..6..7....2..2..3..4..4..6 ..5..6..4..4..4..7....5..5..6..4..7..7....4..5..6..6..4..4....5..5..3..4..6..6 ..5..6..5..5..7..7....5..5..6..4..7..7....4..5..7..7..4..4....7..7..7..6..6..6 CROSSREFS Sequence in context: A192641 A192642 A192643 * A134766 A224826 A122911 Adjacent sequences: A192641 A192642 A192643 * A192645 A192646 A192647 KEYWORD nonn,more AUTHOR R. H. Hardin, Jul 06 2011 STATUS approved

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Last modified December 7 11:41 EST 2023. Contains 367656 sequences. (Running on oeis4.)