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A221023 Equals one maps: number of n X 5 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..3 n X 5 array. 1

%I #8 Aug 03 2018 08:12:53

%S 16,726,30167,1038208,33512960,1073575936,34359074816,1099508973568,

%T 35184361472000,1125899864375296,36028796849094656,

%U 1152921503927369728,36893488144701194240,1180591620706539667456,37778931862913675165696

%N Equals one maps: number of n X 5 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..3 n X 5 array.

%C Column 5 of A221024.

%H R. H. Hardin, <a href="/A221023/b221023.txt">Table of n, a(n) for n = 1..39</a>

%F Empirical: a(n) = 36*a(n-1) - 128*a(n-2) for n>5.

%F Empirical g.f.: x*(16 + 150*x + 6079*x^2 + 45124*x^3 - 1152*x^4) / ((1 - 4*x)*(1 - 32*x)). - _Colin Barker_, Aug 03 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A221024.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 28 2012

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Last modified May 7 01:48 EDT 2024. Contains 372298 sequences. (Running on oeis4.)