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 A221664 Sum of neighbor maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 nX3 array 1

%I

%S 8,64,512,3772,32768,262144,2097152,16777216,134140928,1073741824,

%T 8589934592,68719476736,549755813888,4398033385216,35184372088832,

%U 281474976710656,2251799813685248,18014398509481984,144115185909972992

%N Sum of neighbor maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 nX3 array

%C Column 3 of A221666

%H R. H. Hardin, <a href="/A221664/b221664.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) +360*a(n-5) -2880*a(n-6) -47232*a(n-10) +377856*a(n-11) +2872320*a(n-15) -22978560*a(n-16) -92491776*a(n-20) +739934208*a(n-21) +1689550848*a(n-25) -13516406784*a(n-26) -18150850560*a(n-30) +145206804480*a(n-31) +113850187776*a(n-35) -910801502208*a(n-36) -386547056640*a(n-40) +3092376453120*a(n-41) +549755813888*a(n-45) -4398046511104*a(n-46)

%e Some solutions for n=3

%e ..1..1..1....1..0..0....0..0..1....0..1..1....0..0..1....1..0..0....1..1..0

%e ..0..1..0....0..0..0....0..0..0....0..1..0....0..0..1....1..1..1....1..1..0

%e ..0..0..1....1..1..1....0..1..1....1..0..1....1..0..1....1..1..1....0..0..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 21 2013

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Last modified January 21 05:57 EST 2022. Contains 350473 sequences. (Running on oeis4.)