A186818 Half the number of (n+2)X4 binary arrays with each 3X3 subblock having sum 4 or 5

606, 3988, 25808, 173121, 1190637, 8178097, 56422648, 390661554, 2704080467, 18732156320, 129837515003, 899875661504, 6237831734078, 43243690039607, 299782052613422, 2078270386909730, 14408014447228498, 99886103229478687

Offset

1,1

Comments

Column 2 of A186825

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=5*a(n-1)+13*a(n-2)+80*a(n-3)-419*a(n-4)-760*a(n-5)-1400*a(n-6)+6108*a(n-7)+9112*a(n-8)+3844*a(n-9)-18505*a(n-10)-28582*a(n-11)+63966*a(n-12)-144930*a(n-13)+13184*a(n-14)-284223*a(n-15)+776448*a(n-16)-372906*a(n-17)-226710*a(n-18)+68796*a(n-19)+125280*a(n-20)+96552*a(n-21)-187272*a(n-22)+108864*a(n-23)+233280*a(n-24)-139968*a(n-25)

Example

Some solutions for 6X4 with a(1,1)=0
..0..1..0..0....0..0..1..1....0..0..1..1....0..0..1..1....0..0..1..1
..0..1..1..0....1..0..1..1....1..0..1..0....0..0..0..1....1..1..0..0
..0..1..1..0....0..0..1..0....0..0..1..0....1..1..1..0....0..1..0..1
..0..0..0..1....0..1..1..0....1..0..1..1....0..1..0..1....1..1..0..0
..1..0..1..0....0..1..0..0....0..0..1..0....0..0..0..0....1..0..1..1
..1..1..1..1....1..0..0..1....0..1..0..0....1..1..1..0....0..1..0..1

Crossrefs

Sequence in context: A274765 A249524 A064250 * A283639 A332160 A131215

Adjacent sequences: A186815 A186816 A186817 * A186819 A186820 A186821

Keyword

nonn

Author

R. H. Hardin Feb 27 2011

Status

approved