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A278547 Number of n X 1 0..3 arrays with rows and columns in lexicographic nondecreasing order but with exactly two mistakes. 2
0, 0, 4, 65, 456, 2128, 7728, 23607, 63460, 154518, 347568, 732524, 1461824, 2784600, 5095376, 9002010, 15418728, 25691420, 41763900, 66395595, 103443144, 158220680, 237956160, 352364025, 514357740, 740929410, 1054227720, 1482869934 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 1 of A278553.

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 + (1/20736)*n^9 + (5/8064)*n^8 + (553/172800)*n^7 - (97/28800)*n^6 - (25591/725760)*n^5 + (89/24192)*n^4 + (13607/129600)*n^3 - (47/50400)*n^2 - (289/3960)*n.

Empirical g.f.: x^3*(4 + 17*x - 60*x^2 + 66*x^3 - 32*x^4 + 6*x^5) / (1 - x)^12. - Colin Barker, Mar 22 2018

EXAMPLE

Some solutions for n=4:

..3. .0. .2. .2. .2. .3. .3. .1. .2. .2. .2. .3. .3. .2. .3. .2

..1. .2. .0. .1. .1. .2. .1. .0. .1. .1. .0. .2. .0. .0. .1. .3

..1. .1. .3. .2. .3. .0. .3. .2. .0. .0. .2. .0. .3. .3. .0. .2

..0. .0. .1. .0. .1. .1. .2. .0. .1. .3. .0. .2. .2. .2. .2. .0

CROSSREFS

Cf. A278553.

Sequence in context: A058438 A171959 A041119 * A293562 A331577 A307169

Adjacent sequences:  A278544 A278545 A278546 * A278548 A278549 A278550

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 23 2016

STATUS

approved

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Last modified September 26 13:07 EDT 2021. Contains 347667 sequences. (Running on oeis4.)