A278365 Number of n X 1 0..2 arrays with rows and columns in lexicographic nondecreasing order but with exactly three mistakes.

0, 0, 0, 0, 6, 77, 504, 2304, 8350, 25653, 69576, 171106, 388752, 827190, 1665456, 3198312, 5895396, 10483934, 18062160, 30252180, 49402850, 78855339, 123286440, 189147400, 285219090, 423307755, 619109400, 893275110, 1272714300, 1792178076

Offset

1,5

Comments

Column 1 of A278372.

Links

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

Formula

Empirical: a(n) = (1/39916800)*n^11 + (1/604800)*n^10 + (17/725760)*n^9 - (1/10080)*n^8 - (227/172800)*n^7 + (193/28800)*n^6 - (1273/725760)*n^5 - (1909/60480)*n^4 + (31169/907200)*n^3 + (629/25200)*n^2 - (31/990)*n.

Empirical g.f.: x^5*(2 - x)*(3 - 2*x)*(1 + 2*x - 2*x^2) / (1 - x)^12. - Colin Barker, Mar 22 2018

Example

Some solutions for n=8:
..0. .2. .2. .1. .1. .0. .2. .2. .2. .2. .2. .0. .2. .2. .2. .2
..2. .0. .2. .0. .2. .2. .0. .0. .0. .0. .2. .1. .2. .0. .1. .0
..1. .0. .2. .2. .1. .1. .1. .1. .2. .1. .2. .0. .1. .0. .0. .2
..2. .1. .1. .0. .0. .0. .2. .0. .0. .0. .1. .2. .2. .1. .1. .2
..0. .0. .0. .2. .2. .2. .0. .1. .1. .1. .0. .0. .0. .0. .2. .1
..0. .2. .2. .1. .0. .0. .1. .1. .0. .2. .1. .2. .2. .1. .2. .1
..2. .1. .0. .2. .2. .0. .0. .0. .0. .2. .1. .1. .1. .1. .0. .0
..0. .1. .2. .2. .2. .1. .1. .1. .2. .0. .0. .2. .2. .0. .0. .2

Crossrefs

Cf. A278372.

Sequence in context: A274464 A028979 A082629 * A154642 A282783 A215551

Adjacent sequences: A278362 A278363 A278364 * A278366 A278367 A278368

Keyword

nonn

Author

R. H. Hardin, Nov 19 2016

Status

approved