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A198656
Number of nX2 0..7 arrays with values 0..7 introduced in row major order and each element equal to at least one horizontal or vertical neighbor
1
1, 3, 14, 76, 488, 3521, 28030, 242883, 2267306, 22621072, 239604079, 2677734762, 31381450817, 383270472363, 4847901589642, 63125725801101, 841517900517550, 11429291342102135, 157506922063918536, 2195111769933116471
OFFSET
1,2
COMMENTS
Column 2 of A198661
LINKS
FORMULA
Empirical: a(n) = 50*a(n-1) -973*a(n-2) +8874*a(n-3) -29927*a(n-4) -92230*a(n-5) +939984*a(n-6) -1157338*a(n-7) -7025352*a(n-8) +14473974*a(n-9) +29278108*a(n-10) -54017762*a(n-11) -108264239*a(n-12) +78120984*a(n-13) +276328733*a(n-14) +56831952*a(n-15) -336850101*a(n-16) -307076936*a(n-17) +88644128*a(n-18) +275952224*a(n-19) +124163560*a(n-20) -45062112*a(n-21) -62248400*a(n-22) -20707200*a(n-23) -2210000*a(n-24)
EXAMPLE
Some solutions with all values 0 to 7 for n=8
..0..0....0..0....0..1....0..0....0..0....0..1....0..1....0..1....0..0....0..0
..1..1....1..2....0..1....1..1....1..1....0..1....0..1....0..1....1..1....1..2
..2..2....1..2....2..3....2..2....2..2....2..2....2..2....2..2....2..2....1..2
..3..3....3..4....2..3....3..3....3..3....3..3....3..4....3..3....3..4....3..3
..4..5....3..4....4..5....4..4....4..4....4..5....3..4....4..4....3..4....4..4
..4..5....5..6....4..5....5..6....5..5....4..5....5..5....5..5....5..6....5..6
..6..7....5..6....6..7....5..6....6..6....6..7....6..7....6..6....5..6....5..6
..6..7....7..7....6..7....7..7....7..7....6..7....6..7....7..7....7..7....7..7
CROSSREFS
Sequence in context: A198702 A198621 A198649 * A240402 A048779 A369477
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 28 2011
STATUS
approved