cp's OEIS Frontend

A208840 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.

%I A208840 #7 Jul 22 2025 21:31:32
%S A208840 2,4,4,6,16,6,10,36,36,9,16,100,78,81,14,26,256,282,171,196,22,42,676,
%T A208840 768,855,406,484,35,68,1764,2430,2421,3010,990,1225,56,110,4624,7086,
%U A208840 9801,8736,11242,2485,3136,90,178,12100,21588,31419,49126,33088,44275
%N A208840 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.
%C A208840 Table starts
%C A208840 ..2....4....6.....10.....16.......26.......42........68........110.........178
%C A208840 ..4...16...36....100....256......676.....1764......4624......12100.......31684
%C A208840 ..6...36...78....282....768.....2430.....7086.....21588......64230......193554
%C A208840 ..9...81..171....855...2421.....9801....31419....116919.....394965.....1419849
%C A208840 .14..196..406...3010...8736....49126...169974....833364....3166030....14462714
%C A208840 .22..484..990..11242..33088...272206...992574...6800596...28280758...173714530
%C A208840 .35.1225.2485..44275.131355..1644265..6206445..62470275..277136755..2417186345
%C A208840 .56.3136.6328.179032.533568.10399480.40122936.613538688.2842543480.36689660504
%H A208840 R. H. Hardin, <a href="/A208840/b208840.txt">Table of n, a(n) for n = 1..1465</a>
%F A208840 Empirical for row n:
%F A208840 n=1: a(k)=a(k-1)+a(k-2)
%F A208840 n=2: a(k)=2*a(k-1)+2*a(k-2)-a(k-3)
%F A208840 n=3: a(k)=2*a(k-1)+4*a(k-2)-3*a(k-3)
%F A208840 n=4: a(k)=2*a(k-1)+7*a(k-2)-6*a(k-3)
%F A208840 n=5: a(k)=2*a(k-1)+12*a(k-2)-11*a(k-3)
%F A208840 n=6: a(k)=2*a(k-1)+20*a(k-2)-19*a(k-3)
%F A208840 n=7: a(k)=2*a(k-1)+33*a(k-2)-32*a(k-3)
%e A208840 Some solutions for n=4 k=3
%e A208840 ..1..0..0....1..1..1....1..1..1....1..0..1....0..1..0....0..1..0....0..1..1
%e A208840 ..0..1..1....0..1..0....1..1..0....1..0..0....1..1..0....1..0..1....0..1..1
%e A208840 ..1..0..0....0..1..0....1..1..1....1..1..1....0..1..0....0..1..0....0..1..1
%e A208840 ..0..1..1....0..1..1....1..1..0....1..0..0....0..1..0....1..0..0....1..1..1
%Y A208840 Column 1 is A001611(n+2)
%Y A208840 Column 2 is A207436
%Y A208840 Column 3 is A208103
%Y A208840 Row 1 is A006355(n+2)
%Y A208840 Row 2 is A206981
%Y A208840 Row 3 is A208689
%K A208840 nonn,tabl
%O A208840 1,1
%A A208840 _R. H. Hardin_ Mar 01 2012