A207753 - OEIS

%I #8 Jun 25 2018 12:46:47

%S 9,81,270,900,2100,4900,9450,18225,31185,53361,84084,132496,196560,

%T 291600,413100,585225,799425,1092025,1448370,1920996,2486484,3218436,

%U 4081350,5175625,6449625,8037225,9865800,12110400,14671680,17774656

%N Number of 4 X n 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically.

%C Row 4 of A207752.

%H R. H. Hardin, <a href="/A207753/b207753.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 10*a(n-3) - 5*a(n-4) + 20*a(n-5) - 20*a(n-7) + 5*a(n-8) + 10*a(n-9) - 4*a(n-10) - 2*a(n-11) + a(n-12).

%F Empirical g.f.: x*(9 + 63*x + 72*x^2 + 126*x^3 + 75*x^4 + 25*x^5 - 20*x^6 + 5*x^7 + 10*x^8 - 4*x^9 - 2*x^10 + x^11) / ((1 - x)^7*(1 + x)^5). - _Colin Barker_, Jun 25 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A207752.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 19 2012