A202441 Number of (n+2) X 4 binary arrays avoiding patterns 001 and 110 in rows, columns and nw-to-se diagonals.

138, 226, 376, 574, 836, 1162, 1568, 2054, 2636, 3314, 4104, 5006, 6036, 7194, 8496, 9942, 11548, 13314, 15256, 17374, 19684, 22186, 24896, 27814, 30956, 34322, 37928, 41774, 45876, 50234, 54864, 59766, 64956, 70434, 76216, 82302, 88708, 95434

Offset

1,1

Comments

Column 2 of A202447.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5) for n>6.

Empirical g.f.: 2*x*(69 - 94*x - 13*x^2 + 87*x^3 - 48*x^4 + 7*x^5) / ((1 - x)^4*(1 + x)). - Colin Barker, May 28 2018

Example

Some solutions for n=4:
  0 0 0 0     1 0 1 0     1 1 1 1     0 0 0 0     1 0 1 0
  0 1 1 1     0 0 0 0     1 0 1 0     1 1 1 1     0 0 0 0
  0 1 0 1     1 0 1 0     1 1 1 1     1 0 1 0     1 0 0 0
  0 1 1 1     0 0 0 0     1 0 1 1     1 0 1 1     1 0 0 0
  0 1 1 1     1 0 1 0     1 0 1 1     1 0 1 1     1 0 0 0
  0 1 1 1     0 0 0 0     1 0 1 1     1 0 1 1     1 0 0 0

Crossrefs

Cf. A202447.

Sequence in context: A045045 A108156 A264897 * A187206 A168531 A260133

Adjacent sequences: A202438 A202439 A202440 * A202442 A202443 A202444

Keyword

nonn

Author

R. H. Hardin, Dec 19 2011

Status

approved