A202641 Number of (n+2)X4 binary arrays avoiding patterns 000 and 111 in rows, columns and nw-to-se diagonals

172, 530, 1766, 5948, 19880, 66924, 224940, 755816, 2541276, 8543094, 28716716, 96540806, 324538890, 1090985388, 3667580154, 12329245406, 41447005012, 139332080292, 468390834050, 1574583459558, 5293259411920, 17794285178750

Offset

1,1

Comments

Column 2 of A202647

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) +a(n-3) -28*a(n-4) -30*a(n-5) +56*a(n-6) +71*a(n-7) -64*a(n-8) -74*a(n-9) +42*a(n-10) +39*a(n-11) -18*a(n-12) -9*a(n-13) +6*a(n-14) +a(n-15) -a(n-16) for n>17

Example

Some solutions for n=3
..1..0..0..1....1..0..1..1....1..1..0..1....0..1..1..0....1..0..1..1
..0..0..1..1....1..0..1..0....0..0..1..0....0..1..0..1....1..0..1..0
..0..1..0..0....0..1..0..0....1..1..0..0....1..0..0..1....0..1..0..0
..1..0..0..1....1..1..0..1....0..0..1..1....0..0..1..0....1..0..0..1
..1..0..1..1....1..0..1..1....1..0..1..0....0..1..1..0....0..1..1..0

Crossrefs

Sequence in context: A261706 A043387 A246475 * A234998 A234992 A213992

Adjacent sequences: A202638 A202639 A202640 * A202642 A202643 A202644

Keyword

nonn

Author

R. H. Hardin Dec 22 2011

Status

approved