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A278621 Number of nX2 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake. 1
3, 46, 357, 1952, 8518, 31605, 103546, 307087, 838936, 2138608, 5137407, 11719956, 25549096, 53493458, 108027996, 211167710, 400765157, 740380790, 1334456849, 2351234708, 4056807390, 6864961455, 11409118950, 18644841765, 29994129570 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A278627.

LINKS

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

FORMULA

Empirical: a(n) = (1/1307674368000)*n^15 + (1/12454041600)*n^14 + (149/37362124800)*n^13 + (17/136857600)*n^12 + (3497/1306368000)*n^11 + (241/5806080)*n^10 + (865163/1828915200)*n^9 + (351247/87091200)*n^8 + (2328827/93312000)*n^7 + (698341/6220800)*n^6 + (259070737/718502400)*n^5 + (30620411/39916800)*n^4 + (8765485871/9081072000)*n^3 + (2221837/3603600)*n^2 + (4873/32760)*n

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A278627.

Sequence in context: A196137 A261837 A059624 * A231789 A119401 A124135

Adjacent sequences:  A278618 A278619 A278620 * A278622 A278623 A278624

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 24 2016

STATUS

approved

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Last modified September 24 03:13 EDT 2021. Contains 347623 sequences. (Running on oeis4.)