cp's OEIS Frontend

A229380 T(n,k)=Number of nXk 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 diagonally or antidiagonally.

%I A229380 #6 Jul 23 2025 05:42:09
%S A229380 3,8,8,22,30,22,60,126,126,60,164,518,956,518,164,448,2138,6730,6730,
%T A229380 2138,448,1224,8818,48490,78690,48490,8818,1224,3344,36374,346598,
%U A229380 956866,956866,346598,36374,3344,9136,150038,2486980,11441370,20014278,11441370
%N A229380 T(n,k)=Number of nXk 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 diagonally or antidiagonally.
%C A229380 Table starts
%C A229380 ....3......8.......22.........60..........164............448.............1224
%C A229380 ....8.....30......126........518.........2138...........8818............36374
%C A229380 ...22....126......956.......6730........48490.........346598..........2486980
%C A229380 ...60....518.....6730......78690.......956866.......11441370........138118032
%C A229380 ..164...2138....48490.....956866.....20014278......407900408.......8454015792
%C A229380 ..448...8818...346598...11441370....407900408....13999334726.....492938029980
%C A229380 .1224..36374..2486980..138118032...8454015792...492938029980...29757371834046
%C A229380 .3344.150038.17808604.1657198220.173331549156.17047266083040.1753378119210848
%H A229380 R. H. Hardin, <a href="/A229380/b229380.txt">Table of n, a(n) for n = 1..364</a>
%F A229380 Empirical for column k:
%F A229380 k=1: a(n) = 2*a(n-1) +2*a(n-2)
%F A229380 k=2: a(n) = 4*a(n-1) +a(n-2) -2*a(n-3)
%F A229380 k=3: [order 12]
%F A229380 k=4: [order 24] for n>25
%F A229380 k=5: [order 64] for n>65
%e A229380 Some solutions for n=3 k=4
%e A229380 ..1..0..1..2....1..0..2..1....0..2..0..1....2..0..1..2....2..0..1..2
%e A229380 ..1..2..1..0....1..0..1..2....0..1..2..2....1..2..1..0....1..2..1..0
%e A229380 ..2..1..2..0....2..0..1..0....0..2..1..0....0..0..2..0....1..0..2..2
%Y A229380 Column 1 is A028859
%K A229380 nonn,tabl
%O A229380 1,1
%A A229380 _R. H. Hardin_ Sep 21 2013