A181260 Number of (n+2)X8 binary matrices with every 3X3 block having exactly four 1's.

21024, 27554, 36244, 48846, 79324, 133850, 242784, 526226, 1196428, 2877078, 7542964, 20219426, 55452024, 157207034, 449767204, 1298801406, 3801296524, 11170281290, 32957815824, 97800035426, 290736856828, 865851794598

Offset

1,1

Comments

Column 6 of A181262

Links

R. H. Hardin, Table of n, a(n) for n=1..93

Formula

Empirical: a(n)=6*a(n-1)-11*a(n-2)+42*a(n-3)-216*a(n-4)+396*a(n-5)-719*a(n-6)+3018*a(n-7)-5533*a(n-8)+6498*a(n-9)-20880*a(n-10)+38280*a(n-11)-33444*a(n-12)+75384*a(n-13)-138204*a(n-14)+97848*a(n-15)-134784*a(n-16)+247104*a(n-17)-150336*a(n-18)+93312*a(n-19)-171072*a(n-20)+93312*a(n-21)

Example

Some solutions for 4X8
..0..1..0..1..1..0..1..0....1..1..0..1..0..0..1..1....1..1..0..1..1..0..1..1
..1..0..0..0..0..0..0..0....1..0..1..1..1..1..0..0....0..0..0..0..0..0..0..1
..1..0..1..1..0..1..1..1....0..0..0..0..0..0..1..0....1..1..0..1..1..0..1..0
..0..1..0..1..1..0..1..0....0..1..1..0..0..1..0..1....1..1..0..1..1..0..1..1

Crossrefs

Sequence in context: A231314 A157083 A183639 * A316482 A340897 A371354

Adjacent sequences: A181257 A181258 A181259 * A181261 A181262 A181263

Keyword

nonn

Author

R. H. Hardin, Oct 10 2010

Status

approved