A181258 Number of (n+2)X6 binary matrices with every 3X3 block having exactly four 1's

2484, 3942, 6360, 10818, 22512, 48846, 112500, 289830, 764832, 2072106, 5854728, 16700214, 48109644, 140771982, 413533560, 1219726098, 3620006112, 10762255326, 32052060900, 95704407030, 285982189392, 855223829946, 2560357197048

Offset

1,1

Comments

Column 4 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 4X6
..0..1..1..0..0..1....1..0..0..1..0..1....0..0..1..0..0..1....0..1..0..1..1..0
..0..0..0..0..1..0....1..0..0..1..0..0....1..1..1..1..0..0....1..1..0..0..1..1
..0..1..1..0..1..1....1..0..1..1..0..0....0..0..0..0..1..1....0..0..1..0..0..0
..0..1..1..0..0..1....1..0..0..1..0..1....0..0..1..0..0..1....0..0..1..1..0..1

Crossrefs

Sequence in context: A235763 A235546 A214477 * A258442 A255750 A255757

Adjacent sequences: A181255 A181256 A181257 * A181259 A181260 A181261

Keyword

nonn

Author

R. H. Hardin Oct 10 2010

Status

approved