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A278728
Number of n X 2 0..3 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.
1
6, 152, 1947, 17352, 121520, 712406, 3633649, 16547278, 68531079, 261693631, 931194981, 3113638802, 9849622993, 29642927267, 85271613063, 235393492799, 625708778733, 1606286648601, 3992748071821, 9631887926896, 22595573914587
OFFSET
1,1
COMMENTS
Column 2 of A278734.
FORMULA
Empirical polynomial of degree 28 (see link above).
EXAMPLE
Some solutions for n=4
..2..2. .1..1. .2..1. .1..1. .2..0. .1..0. .3..0. .0..0. .1..1. .2..2
..3..0. .1..1. .2..2. .3..2. .3..2. .3..2. .3..0. .3..1. .2..1. .3..0
..0..2. .0..0. .1..0. .2..2. .0..0. .0..0. .3..0. .1..0. .2..2. .2..3
..0..2. .1..1. .1..0. .2..3. .2..0. .0..1. .2..1. .1..0. .1..0. .3..2
CROSSREFS
Cf. A278734.
Sequence in context: A168654 A147796 A003766 * A221689 A354752 A319036
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 27 2016
STATUS
approved