A204716 Number of (n+1) X 2 0..1 arrays with the permanents of 2 X 2 subblocks nondecreasing rightwards and downwards.

16, 51, 156, 450, 1267, 3490, 9490, 25545, 68286, 181584, 481021, 1270576, 3348916, 8812575, 23161632, 60817950, 159583495, 418515070, 1097126806, 2875195509, 7533120066, 19733485356, 51685977361, 135361729420, 354473776312

Offset

1,1

Comments

Column 1 of A204723.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - a(n-2) - 9*a(n-3) + 4*a(n-4) + 5*a(n-5) - 2*a(n-6).

Empirical g.f.: x*(16 - 13*x - 32*x^2 + 21*x^3 + 18*x^4 - 8*x^5) / ((1 - x)*(1 + x)^2*(1 - 2*x)*(1 - 3*x + x^2)). - Colin Barker, Mar 03 2018

Example

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

Crossrefs

Cf. A204723.

Sequence in context: A204723 A204962 A080860 * A192248 A363350 A297640

Adjacent sequences: A204713 A204714 A204715 * A204717 A204718 A204719

Keyword

nonn

Author

R. H. Hardin, Jan 18 2012

Status

approved