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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

%I

%S 2,4,11,31,89,253,748,2214,6615,19767,59217,177393,531930,1595052,

%T 4784427,14351103,43051113,129146733,387433620,1162281150,3486823767,

%U 10460412279,31381177761,94143356001,282429890802,847289140884

%N 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.

%H R. H. Hardin, <a href="/A263375/b263375.txt">Table of n, a(n) for n = 1..210</a>

%F 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).

%F 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

%e Some solutions for n=4:

%e ..3..3....0..0....3..3....0..0....3..3....3..3....0..0....1..4....3..3....0..0

%e ..0..0....0..0....0..0....1..4....1..4....0..0....0..0....3..3....3..3....0..0

%e ..0..0....3..3....3..3....3..3....1..4....0..0....3..3....0..0....3..3....0..0

%e ..1..4....1..4....0..0....3..3....0..0....3..3....3..3....1..4....1..4....0..0

%e ..1..4....1..4....3..3....1..4....0..0....0..0....0..0....3..3....1..4....0..0

%Y Column 1 of A263382.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 16 2015

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Last modified October 16 20:36 EDT 2021. Contains 348047 sequences. (Running on oeis4.)