A317761 - OEIS

%I #18 Dec 12 2021 02:23:10

%S 16,42,52,72,109,177,302,532,955,1733,3164,5796,10637,19541,35918,

%T 66040,121443,223345,410772,755504,1389565,2555785,4700798,8646092,

%U 15902619,29249453,53798108,98950124,181997629,334745805,615693502,1132436880

%N Number of n X 5 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 5 of A317764.

%H R. H. Hardin, <a href="/A317761/b317761.txt">Table of n, a(n) for n = 1..210</a>

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

%e Some solutions for n=5:

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

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

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

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

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

%Y Cf. A317764.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 06 2018