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

1,4

Comments

Column 2 of A278855.

Links

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

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

Example

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

Crossrefs

Cf. A278855.

Sequence in context: A160222 A088890 A108178 * A294290 A352304 A362393

Adjacent sequences: A278846 A278847 A278848 * A278850 A278851 A278852

Keyword

nonn

Author

R. H. Hardin, Nov 29 2016

Status

approved