A220155 Number of 3Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 3Xn array.

10, 26, 77, 254, 645, 1413, 2841, 5412, 9905, 17565, 30369, 51437, 85641, 140477, 227277, 362851, 571663, 888660, 1362889, 2062054, 3078183, 4534594, 6594369, 9470566, 13438421, 18849815, 26150305, 35899043, 48791933, 65688403, 87642197

Offset: 1

Author

R. H. Hardin Dec 06 2012

Keywords

• nonn

Comments

Row 3 of A220153

Examples

			Some solutions for n=3
..2..0..0....1..0..1....1..1..1....0..0..1....1..0..0....1..0..0....0..0..0
..2..0..0....1..0..0....1..1..1....0..0..0....2..2..1....2..1..1....2..1..0
..2..0..0....2..2..1....2..1..1....1..1..0....2..2..2....2..2..2....2..1..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (1/362880)*n^9 + (1/40320)*n^8 - (11/60480)*n^7 - (49/2880)*n^6 + (10837/17280)*n^5 - (30473/5760)*n^4 + (1003267/45360)*n^3 + (41353/3360)*n^2 - (594077/2520)*n + 361 for n>6