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A207256 Number of 5 X n 0..1 arrays avoiding 0 0 1 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically. 1

%I #8 Jun 21 2018 10:31:50

%S 16,256,1232,3776,9072,18688,34608,59264,95568,146944,217360,311360,

%T 434096,591360,789616,1036032,1338512,1705728,2147152,2673088,3294704,

%U 4024064,4874160,5858944,6993360,8293376,9776016,11459392,13362736

%N Number of 5 X n 0..1 arrays avoiding 0 0 1 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically.

%C Row 5 of A207254.

%H R. H. Hardin, <a href="/A207256/b207256.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (4/15)*n^5 + (32/3)*n^4 + (44/3)*n^3 - (32/3)*n^2 + (16/15)*n.

%F Conjectures from _Colin Barker_, Jun 21 2018: (Start)

%F G.f.: 16*x*(1 + 10*x - 4*x^2 - 6*x^3 + x^4) / (1 - x)^6.

%F a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

%F (End)

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A207254.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 16 2012

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Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)