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, 3, 14, 76, 488, 3521, 28030, 242883, 2267306, 22621072, 239604079, 2677734762, 31381450817, 383270472363, 4847901589642, 63125725801101, 841517900517550, 11429291342102135, 157506922063918536, 2195111769933116471

Offset: 1

Author

R. H. Hardin Oct 28 2011

Keywords

• nonn

Comments

Column 2 of A198661

Examples

			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
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

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) [phone]*a(n-9) [phone]*a(n-10) -54017762*a(n-11) -108264239*a(n-12) [phone]*a(n-13) [phone]*a(n-14) [phone]*a(n-15) -336850101*a(n-16) -307076936*a(n-17) [phone]*a(n-18) [phone]*a(n-19) [phone]*a(n-20) -45062112*a(n-21) -62248400*a(n-22) -20707200*a(n-23) -2210000*a(n-24)