A187310 Half the number of (n+2)X4 binary arrays with each 3X3 subblock having sum 3, 4, 5 or 6

1472, 18792, 237650, 3029032, 38586679, 491649803, 6264576384, 79823385565, 1017110076243, 12960036515411, 165137035418995, 2104179269485804, 26811492792678275, 341632558227269955, 4353088643047986551

Offset

1,1

Comments

Column 2 of A187317

Links

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

Formula

Empirical: a(n)=12*a(n-1)+15*a(n-2)-37*a(n-3)-410*a(n-4)-551*a(n-5)+3600*a(n-6)+5558*a(n-7)-8726*a(n-8)-46631*a(n-9)-18772*a(n-10)+120881*a(n-11)+191220*a(n-12)-28195*a(n-13)-325390*a(n-14)-249390*a(n-15)+47034*a(n-16)+328056*a(n-17)+269892*a(n-18)-88272*a(n-19)-548424*a(n-20)-327888*a(n-21)+220320*a(n-22)+178848*a(n-23)-128304*a(n-24)-139968*a(n-25)

Example

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

Crossrefs

Sequence in context: A252521 A237379 A237144 * A167575 A157505 A290723

Adjacent sequences: A187307 A187308 A187309 * A187311 A187312 A187313

Keyword

nonn

Author

R. H. Hardin Mar 08 2011

Status

approved