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A263375 Number of (n+1) X (1+1) 0..4 arrays with each row and column divisible by 9, read as a base-5 number with top and left being the most significant digits. 1
2, 4, 11, 31, 89, 253, 748, 2214, 6615, 19767, 59217, 177393, 531930, 1595052, 4784427, 14351103, 43051113, 129146733, 387433620, 1162281150, 3486823767, 10460412279, 31381177761, 94143356001, 282429890802, 847289140884 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 3*a(n-2) - 9*a(n-3) + 3*a(n-6) - 9*a(n-7) - 9*a(n-8) + 27*a(n-9).

Empirical g.f.: x*(2 - 2*x - 7*x^2 + 4*x^3 - x^4 - 8*x^5 - 5*x^6 + 18*x^7 + 27*x^8) / ((1 - 3*x)*(1 - 3*x^2)*(1 - 3*x^6)). - Colin Barker, Jan 01 2019

EXAMPLE

Some solutions for n=4:

..3..3....0..0....3..3....0..0....3..3....3..3....0..0....1..4....3..3....0..0

..0..0....0..0....0..0....1..4....1..4....0..0....0..0....3..3....3..3....0..0

..0..0....3..3....3..3....3..3....1..4....0..0....3..3....0..0....3..3....0..0

..1..4....1..4....0..0....3..3....0..0....3..3....3..3....1..4....1..4....0..0

..1..4....1..4....3..3....1..4....0..0....0..0....0..0....3..3....1..4....0..0

CROSSREFS

Column 1 of A263382.

Sequence in context: A325922 A148160 A148161 * A148162 A148163 A274775

Adjacent sequences:  A263372 A263373 A263374 * A263376 A263377 A263378

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 16 2015

STATUS

approved

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Last modified September 26 20:34 EDT 2021. Contains 347672 sequences. (Running on oeis4.)