A278671 Number of n X 3 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.

4, 33, 158, 579, 1801, 4999, 12727, 30218, 67651, 143936, 292799, 572247, 1078870, 1968906, 3488570, 6016844, 10124758, 16656179, 26836284, 42415243, 65856199, 100578425, 151268585, 224275350, 328105245, 474040554, 676903413, 955993903

Offset

1,1

Links

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

Formula

Empirical: a(n) = (1/39916800)*n^11 + (1/907200)*n^10 + (17/725760)*n^9 + (19/60480)*n^8 + (3691/1209600)*n^7 + (1003/43200)*n^6 + (21115/145152)*n^5 + (106243/181440)*n^4 + (1170209/907200)*n^3 + (35051/25200)*n^2 + (7783/13860)*n.

Empirical g.f.: x*(4 - 15*x + 26*x^2 - 19*x^3 + x^4 + 8*x^5 - 5*x^6 + x^7) / (1 - x)^12. - Colin Barker, Feb 10 2019

Example

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

Crossrefs

Column 3 of A278676.

Sequence in context: A364946 A209034 A095671 * A273676 A013192 A273700

Adjacent sequences: A278668 A278669 A278670 * A278672 A278673 A278674

Keyword

nonn

Author

R. H. Hardin, Nov 25 2016

Status

approved