A206199 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly one clockwise edge increases.

256, 480, 1768, 7388, 29724, 117084, 468968, 1878808, 7493008, 29925508, 119605588, 477741796, 1908251600, 7623408272, 30453658424, 121651754668, 485967430220, 1941313945708, 7755000190904, 30979095429960, 123753089725152

Offset

1,1

Comments

Column 1 of A206206.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 17*a(n-3) - 5*a(n-4) + 2*a(n-5) for n>6.

Empirical g.f.: 4*x*(64 - 72*x + 82*x^2 - 567*x^3 + 170*x^4 - 64*x^5) / (1 - 3*x - 17*x^3 + 5*x^4 - 2*x^5). - Colin Barker, Jun 14 2018

Example

Some solutions for n=4:
  1 3   1 2   2 0   1 1   0 2   1 3   1 0   3 3   1 0   2 2
  1 1   1 2   2 2   1 3   0 0   2 2   0 0   1 1   0 0   1 1
  1 1   1 2   2 2   3 3   0 0   2 2   0 0   1 1   0 0   1 1
  3 0   1 1   0 0   3 3   1 0   2 0   0 2   2 3   1 2   2 0
  3 3   1 1   0 0   2 2   1 0   2 3   1 1   2 2   1 1   3 3

Crossrefs

Cf. A206206.

Sequence in context: A223693 A223064 A206206 * A271811 A255998 A309092

Adjacent sequences: A206196 A206197 A206198 * A206200 A206201 A206202

Keyword

nonn

Author

R. H. Hardin, Feb 04 2012

Status

approved