A219382 Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 2 X n array.

6, 7, 14, 25, 40, 66, 103, 157, 234, 341, 486, 678, 927, 1244, 1641, 2131, 2728, 3447, 4304, 5316, 6501, 7878, 9467, 11289, 13366, 15721, 18378, 21362, 24699, 28416, 32541, 37103, 42132, 47659, 53716, 60336, 67553, 75402, 83919, 93141, 103106

Offset

1,1

Comments

Row 2 of A219381.

Links

R. H. Hardin, Table of n, a(n) for n = 1..165

Formula

Empirical: a(n) = (1/24)*n^4 - (1/4)*n^3 + (35/24)*n^2 + (15/4)*n - 9 for n>5.

Conjectures from Colin Barker, Jul 26 2018: (Start)

G.f.: x*(6 - 23*x + 39*x^2 - 35*x^3 + 15*x^4 + 5*x^5 - 14*x^6 + 13*x^7 - 6*x^8 + x^9) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>10.

(End)

Example

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

Crossrefs

Cf. A219381.

Sequence in context: A058556 A332045 A022311 * A047915 A084382 A315842

Adjacent sequences: A219379 A219380 A219381 * A219383 A219384 A219385

Keyword

nonn

Author

R. H. Hardin, Nov 19 2012

Status

approved