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A251148 Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries. 1

%I #16 Nov 26 2018 16:16:51

%S 853,1075,1413,1987,2925,4491,7101,11491,18917,31587,53389,91275,

%T 157789,275843,487717,872259,1577901,2886539,5337725,9971363,18803813,

%U 35765155,68549453,132276107,256749085,500872771,981317541,1929582211,3805684077

%N Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.

%H R. H. Hardin, <a href="/A251148/b251148.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) - 5*a(n-3) + a(n-4) + 2*a(n-5).

%F Empirical g.f.: x*(853 - 1484*x - 1812*x^2 + 2013*x^3 + 1486*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)). - _Colin Barker_, Nov 26 2018

%e Some solutions for n=4:

%e ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1

%e ..2..1..2..0..2..0..1..0....1..1..1..1..2..1..2..0....2..1..1..2..1..0..1..1

%e ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1

%e ..1..2..1..1..1..1..0..1....1..1..1..1..2..1..2..0....2..1..1..2..1..0..1..1

%e ..1..0..1..1..1..1..2..1....2..0..2..0..1..0..1..1....0..1..1..0..1..2..1..1

%Y Column 7 of A251149.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 30 2014

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Last modified February 23 19:35 EST 2024. Contains 370283 sequences. (Running on oeis4.)