A223784 - OEIS

%I #6 Jan 20 2024 17:03:16

%S 22,484,8635,151580,2703137,48302789,862007289,15379566078,

%T 274427327200,4896915028511,87380287912506,1559204462831053,

%U 27822300189794631,496458709513621497,8858765510668046944,158075026701646689756

%N Number of n X 3 0..2 arrays with rows, diagonals and antidiagonals unimodal.

%C Column 3 of A223789.

%H R. H. Hardin, <a href="/A223784/b223784.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 18*a(n-1) -24*a(n-2) +364*a(n-3) +605*a(n-4) -5879*a(n-5) -3267*a(n-6) -28514*a(n-7) -68422*a(n-8) +215872*a(n-9) +381625*a(n-10) +110428*a(n-11) +62650*a(n-12) -42873*a(n-13) -108576*a(n-14) -28080*a(n-15).

%e Some solutions for n=3

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

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

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

%Y Cf. A223789.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 27 2013