A181257 Number of (n+2)X5 binary matrices with every 3X3 block having exactly four 1's

906, 1684, 3190, 6360, 14974, 36244, 91122, 247372, 681262, 1906656, 5492470, 15919324, 46439466, 136964884, 405022630, 1200958440, 3576601774, 10663915684, 31832655522, 95194295452, 284820551902, 852619865136, 2554290632230

Offset

1,1

Comments

Column 3 of A181262

Links

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

Formula

Empirical: a(n)=4*a(n-1)-3*a(n-2)+36*a(n-3)-144*a(n-4)+108*a(n-5)-503*a(n-6)+2012*a(n-7)-1509*a(n-8)+3480*a(n-9)-13920*a(n-10)+10440*a(n-11)-12564*a(n-12)+50256*a(n-13)-37692*a(n-14)+22464*a(n-15)-89856*a(n-16)+67392*a(n-17)-15552*a(n-18)+62208*a(n-19)-46656*a(n-20)

Example

Some solutions for 5X5
..1..1..0..1..0....0..1..1..0..1....0..0..0..0..1....0..0..1..0..0
..0..1..0..1..1....0..1..1..0..0....0..1..1..1..0....1..0..1..0..0
..1..0..0..0..1....0..0..0..0..1....1..0..1..0..0....0..0..1..1..0
..1..1..0..1..0....1..0..1..1..0....0..0..0..0..1....0..0..1..0..0
..0..1..0..1..1....1..1..0..1..0....0..1..1..1..0....1..1..0..0..1

Crossrefs

Sequence in context: A235949 A330284 A330303 * A235242 A270446 A006917

Adjacent sequences: A181254 A181255 A181256 * A181258 A181259 A181260

Keyword

nonn

Author

R. H. Hardin Oct 10 2010

Status

approved