A300344 Number of n X 2 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 2, 6, 15, 37, 90, 223, 550, 1355, 3341, 8237, 20307, 50064, 123426, 304290, 750185, 1849478, 4559634, 11241151, 27713513, 68323858, 168443083, 415273274, 1023799191, 2524036217, 6222664445, 15341124083, 37821433280, 93243546406

Offset

1,2

Comments

Column 2 of A300350.

Links

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

Simon Plouffe, Conjectures of the OEIS, as of June 20, 2018.

Formula

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

Empirical g.f.: -x*(-2*x^4-2*x^3-2*x^2-x-1)/(-x^5-2*x^4-3*x^3-2*x^2-x+1). - Simon Plouffe, Jun 20 2018

Example

Some solutions for n=5:
  0 0   0 1   0 0   0 1   0 0   0 0   0 1   0 0   0 0   0 1
  0 1   0 1   1 0   0 1   1 1   0 1   0 1   1 0   1 1   0 1
  1 0   1 0   1 0   0 1   0 1   1 0   0 1   1 1   0 1   0 1
  0 1   1 0   1 0   0 1   0 1   0 1   1 0   0 1   0 0   0 0
  1 1   1 1   1 1   0 0   0 1   0 1   1 0   0 1   1 1   1 1

Crossrefs

Cf. A300350.

Sequence in context: A335903 A291414 A098790 * A018019 A331347 A306463

Adjacent sequences: A300341 A300342 A300343 * A300345 A300346 A300347

Keyword

nonn

Author

R. H. Hardin, Mar 03 2018

Status

approved