A204833 Number of (n+1) X 2 0..2 arrays with the permanents of all 2 X 2 subblocks equal and nonzero.

56, 132, 318, 804, 2048, 5304, 13786, 36074, 94630, 249116, 657120, 1737412, 4601434, 12208078, 32435606, 86299392, 229889712, 613103960, 1636797162, 4373968322, 11698648166, 31314844564, 83885825808, 224868555948

Offset

1,1

Comments

Column 1 of A204840.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 8*a(n-2) - 41*a(n-3) - 21*a(n-4) + 152*a(n-5) + 18*a(n-6) - 237*a(n-7) + 12*a(n-8) + 130*a(n-9) - 24*a(n-10).

Empirical g.f.: 2*x*(28 - 46*x - 329*x^2 + 386*x^3 + 1438*x^4 - 1011*x^5 - 2622*x^6 + 955*x^7 + 1599*x^8 - 326*x^9) / ((1 - x)*(1 - 2*x^2)*(1 - x - 3*x^2)*(1 - x - 4*x^2)*(1 - x - 5*x^2 + x^3)). - Colin Barker, Jun 10 2018

Example

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

Crossrefs

Cf. A204840.

Sequence in context: A306935 A253418 A204840 * A121736 A107937 A044307

Adjacent sequences: A204830 A204831 A204832 * A204834 A204835 A204836

Keyword

nonn

Author

R. H. Hardin, Jan 19 2012

Status

approved