A278849 Number of nX2 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly three mistakes.

0, 0, 1, 25, 239, 1486, 7072, 27828, 94720, 287298, 793024, 2023332, 4828941, 10881820, 23327332, 47861324, 94458120, 180072500, 332769135, 597905471, 1047219371, 1791963626, 3001600740, 4930040800, 7951993320, 12612734550

Offset: 1

Author

R. H. Hardin, Nov 29 2016

Keywords

• nonn

Comments

Column 2 of A278855.

Examples

			Some solutions for n=4
..1..1. .1..1. .0..1. .0..1. .1..1. .0..1. .1..1. .1..1. .1..1. .0..0
..0..1. .0..1. .1..1. .0..0. .0..0. .1..1. .0..1. .0..1. .1..0. .1..1
..1..0. .0..0. .1..0. .1..1. .0..1. .0..1. .1..1. .1..1. .0..1. .0..1
..0..1. .1..1. .0..1. .0..1. .0..0. .0..0. .0..0. .1..0. .0..0. .0..0
		

Links

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

Crossrefs

Cf. A278855.

Formula

Empirical: a(n) = (1/87178291200)*n^14 + (1/958003200)*n^13 + (43/958003200)*n^12 + (893/958003200)*n^11 + (863/87091200)*n^10 + (11/358400)*n^9 + (28333/609638400)*n^8 + (32029/87091200)*n^7 + (13219/21772800)*n^6 - (119603/10886400)*n^5 - (291547/59875200)*n^4 + (883781/19958400)*n^3 + (127307/30270240)*n^2 - (467/13860)*n