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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
OFFSET
1,2
LINKS
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: A357420 A371407 A369505 * A268075 A202545 A131812
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 25 2016
STATUS
approved