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A278604
Number of nX1 0..3 arrays with rows and columns in lexicographic nondecreasing order but with exactly three mistakes.
2
0, 0, 0, 1, 56, 728, 5328, 27876, 116304, 411334, 1281280, 3606980, 9346624, 22597760, 51507280, 111578412, 231211152, 460720740, 886647920, 1653955415, 2999760280, 5303659240, 9161558720, 15492338160, 25689792960, 41836287690
OFFSET
1,5
COMMENTS
Column 1 of A278610.
LINKS
FORMULA
Empirical: a(n) = (1/1307674368000)*n^15 + (1/10897286400)*n^14 + (47/9340531200)*n^13 + (17/119750400)*n^12 + (193/93312000)*n^11 + (37/3628800)*n^10 - (26401/457228800)*n^9 - (47183/76204800)*n^8 + (1918993/1306368000)*n^7 + (3793/544320)*n^6 - (386327/25660800)*n^5 - (151381/6652800)*n^4 + (441553891/9081072000)*n^3 + (275711/16816800)*n^2 - (191/5460)*n
EXAMPLE
Some solutions for n=6
..2. .2. .2. .3. .3. .2. .3. .0. .1. .1. .2. .2. .2. .3. .3. .3
..1. .1. .1. .2. .2. .1. .1. .3. .2. .2. .1. .0. .1. .0. .2. .2
..0. .1. .2. .3. .0. .0. .2. .2. .1. .0. .1. .1. .0. .2. .1. .3
..2. .3. .1. .1. .0. .1. .1. .1. .0. .3. .3. .0. .3. .1. .2. .1
..0. .2. .3. .0. .3. .3. .0. .3. .2. .2. .2. .2. .1. .3. .1. .3
..1. .0. .0. .2. .2. .0. .0. .0. .1. .1. .1. .0. .2. .0. .3. .1
CROSSREFS
Cf. A278610.
Sequence in context: A136006 A138410 A240269 * A201098 A190419 A105940
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2016
STATUS
approved