A219501 Number of n X 7 arrays of the minimum value of corresponding elements and their horizontal or vertical neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..1 n X 7 array.

7, 13, 45, 126, 281, 550, 995, 1703, 2793, 4424, 6804, 10200, 14949, 21470, 30277, 41993, 57365, 77280, 102782, 135090, 175617, 225990, 288071, 363979, 456113, 567176, 700200, 858572, 1046061, 1266846, 1525545, 1827245, 2177533, 2582528

Offset

1,1

Comments

Column 7 of A219502.

Links

Table of n, a(n) for n=1..34.

Formula

Empirical: a(n) = (1/720)*n^6 + (1/240)*n^5 + (23/144)*n^4 + (13/16)*n^3 + (331/180)*n^2 + (311/60)*n - 27 for n>3.

Example

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

Crossrefs

Cf. A219502.

Sequence in context: A287685 A159305 A146648 * A267310 A153119 A166703

Adjacent sequences: A219498 A219499 A219500 * A219502 A219503 A219504

Keyword

nonn

Author

R. H. Hardin, Nov 20 2012

Status

approved