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 A224556 Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent. 1

%I #7 Aug 31 2018 09:27:10

%S 263,246,320,395,540,740,988,1351,1881,2623,3689,5243,7494,10763,

%T 15535,22504,32685,47578,69377,101291,148029,216494,316798,463762,

%U 679110,994678,1457123,2134826,3128004,4583531,6716662,9842869,14424498

%N Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent.

%C Column 5 of A224559.

%H R. H. Hardin, <a href="/A224556/b224556.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 5*a(n-3) - 4*a(n-4) + 3*a(n-5) - a(n-6) for n>8.

%F Empirical g.f.: x*(263 - 806*x + 914*x^2 - 724*x^3 + 702*x^4 - 455*x^5 + 98*x^6 + 5*x^7) / ((1 - x)^3*(1 - x - x^3)). - _Colin Barker_, Aug 31 2018

%e Some solutions for n=3:

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

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

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

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

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

%Y Cf. A224559.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 10 2013

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Last modified August 6 20:30 EDT 2024. Contains 374983 sequences. (Running on oeis4.)