A263367 - OEIS

%I #4 Oct 16 2015 07:29:44

%S 1,2,7,29,112,367,1359,5370,21447,86013,343936,1371301,5479081,

%T 21913562,87653287,350634149,1402534912,5609859607,22439049159,

%U 89756056050,359024196327,1436098422693,5744393762896,22977556193101,91910198451361

%N Number of (n+1)X(2+1) 0..2 arrays with each row and column divisible by 7, read as a base-3 number with top and left being the most significant digits.

%C Column 2 of A263373.

%H R. H. Hardin, <a href="/A263367/b263367.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +101*a(n-6) -404*a(n-7) -2159*a(n-12) +8636*a(n-13) +2059*a(n-18) -8236*a(n-19)

%e Some solutions for n=4

%e ..0..2..1....0..0..0....0..2..1....0..0..0....1..1..2....0..2..1....0..2..1

%e ..0..2..1....2..1..0....2..1..0....0..0..0....2..1..0....0..0..0....1..1..2

%e ..0..0..0....1..1..2....0..0..0....2..1..0....0..0..0....0..0..0....0..0..0

%e ..0..2..1....0..2..1....0..2..1....1..1..2....1..1..2....0..2..1....0..2..1

%e ..0..2..1....0..0..0....2..1..0....0..2..1....2..1..0....0..0..0....1..1..2

%Y Cf. A263373.

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 16 2015