A301965 - OEIS

%I #4 Mar 29 2018 13:02:49

%S 4,13,16,25,41,74,132,239,437,800,1468,2697,4957,9114,16760,30823,

%T 56689,104264,191768,352713,648737,1193210,2194652,4036591,7424445,

%U 13655680,25116708,46196825,84969205,156282730,287448752,528700679,972432153

%N Number of 3Xn 0..1 arrays with every element equal to 0, 1 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

%C Row 3 of A301964.

%H R. H. Hardin, <a href="/A301965/b301965.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..1..1..0. .0..1..0..1..0. .0..0..1..1..0. .0..1..0..0..1

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

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

%Y Cf. A301964.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 29 2018