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A268052 Number of n X 4 0..2 arrays with new values introduced in each row and column in sequential order starting with zero. 1
1, 8, 86, 1082, 14554, 200818, 2796826, 39082562, 546791114, 7653252338, 107136417466, 1499864270242, 20997871916074, 293969067496658, 4115561248327706, 57617828993493122, 806649463493495434 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 21*a(n-1) - 108*a(n-2) + 140*a(n-3).

Conjectures from Colin Barker, Jan 11 2019: (Start)

G.f.: x*(1 - 13*x + 26*x^2) / ((1 - 2*x)*(1 - 5*x)*(1 - 14*x)).

a(n) = (105*2^n + 196*5^n + 25*2^(1+n)*7^n) / 1890.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0

..0..1..0..1....0..1..1..0....0..0..1..1....0..1..1..1....0..1..0..1

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

..0..1..0..0....0..1..0..1....0..1..1..0....0..1..0..1....0..1..1..1

CROSSREFS

Column 4 of A268056.

Sequence in context: A261501 A180582 A230621 * A268075 A202545 A131812

Adjacent sequences:  A268049 A268050 A268051 * A268053 A268054 A268055

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 25 2016

STATUS

approved

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Last modified January 22 05:19 EST 2022. Contains 350481 sequences. (Running on oeis4.)