cp's OEIS Frontend

A204700 Number of nX3 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically or nw-to-se diagonally, and new values 0..2 introduced in row major order.

%I A204700 #8 Jul 22 2025 18:14:27
%S A204700 4,96,1417,22869,362020,5767683,91733605,1459710274,23224443905,
%T A204700 369522237415,5879375305236,93545539546075,1488382733670257,
%U A204700 23681339437114202,376788704103588493,5995004229216188035
%N A204700 Number of nX3 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically or nw-to-se diagonally, and new values 0..2 introduced in row major order.
%C A204700 Column 3 of A204705
%H A204700 R. H. Hardin, <a href="/A204700/b204700.txt">Table of n, a(n) for n = 1..210</a>
%F A204700 Empirical: a(n) = 9*a(n-1) +117*a(n-2) -24*a(n-3) -1482*a(n-4) +884*a(n-5) +6805*a(n-6) -7217*a(n-7) +875*a(n-8) -9444*a(n-9) +23926*a(n-10) -157560*a(n-11) +235676*a(n-12) +268960*a(n-13) -735296*a(n-14) +199456*a(n-15) +747264*a(n-16) -760384*a(n-17) -340800*a(n-18) +784192*a(n-19) -38208*a(n-20) -346880*a(n-21) +138880*a(n-22) +50176*a(n-23) -91904*a(n-24) +17408*a(n-25) +25600*a(n-26) -8192*a(n-27) -4096*a(n-28) for n>31
%e A204700 Some solutions for n=5
%e A204700 ..0..1..0....0..0..1....0..1..2....0..0..1....0..1..0....0..0..1....0..0..1
%e A204700 ..2..1..2....2..2..0....0..0..1....1..2..2....0..1..1....1..0..1....2..0..1
%e A204700 ..2..2..1....0..2..1....2..2..1....2..1..2....1..0..2....2..1..2....2..1..2
%e A204700 ..0..1..1....2..0..1....1..2..2....2..2..0....1..2..2....0..2..2....1..2..1
%e A204700 ..0..0..2....2..0..2....0..0..1....0..1..1....2..0..0....2..0..0....0..2..1
%K A204700 nonn
%O A204700 1,1
%A A204700 _R. H. Hardin_ Jan 18 2012