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A253441 Number of (7+1) X (n+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally. 1

%I #7 Dec 13 2018 05:16:50

%S 613,612,625,660,732,876,1164,1740,2892,5196,9804,19020,37452,74316,

%T 148044,295500,590412,1180236,2359884,4719180,9437772,18874956,

%U 37749324,75498060,150995532,301990476,603980364,1207960140,2415919692,4831838796

%N Number of (7+1) X (n+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

%H R. H. Hardin, <a href="/A253441/b253441.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical: a(n) = 9*2^(n-1) + 588 for n>3.

%F Empirical g.f.: x*(613 - 1227*x + 15*x^2 + 9*x^3 + 2*x^4) / ((1 - x)*(1 - 2*x)). - _Colin Barker_, Dec 13 2018

%e Some solutions for n=4:

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

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

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

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

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

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

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

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

%Y Row 7 of A253435.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 31 2014

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)