A219933 Number of nX2 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..3 nX2 array

4, 23, 76, 208, 519, 1212, 2670, 5574, 11076, 21043, 38390, 67522, 114907, 189804, 305172, 478788, 734604, 1104375, 1629592, 2363756, 3375031, 4749316, 6593778, 9040890, 12253020, 16427619, 21803058, 28665166, 37354523, 48274564, 61900552

Offset

1,1

Comments

Column 2 of A219939

Links

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

Formula

Empirical: a(n) = (1/20160)*n^8 + (1/1680)*n^7 + (1/1440)*n^6 + (23/240)*n^5 - (613/2880)*n^4 + (211/120)*n^3 + (11149/5040)*n^2 + (61/420)*n

Example

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

Crossrefs

Sequence in context: A226411 A226342 A071246 * A304305 A316204 A305771

Adjacent sequences: A219930 A219931 A219932 * A219934 A219935 A219936

Keyword

nonn

Author

R. H. Hardin Dec 01 2012

Status

approved