A226845 Number of n X 1 (0,1,2) arrays of permanents of 2 X 2 subblocks of some (n+1) X 2 binary array.

3, 9, 23, 57, 145, 373, 957, 2449, 6267, 16045, 41083, 105185, 269297, 689465, 1765209, 4519393, 11570803, 29624209, 75845551, 194184025, 497160801, 1272858861, 3258844373, 8343475473, 21361432171, 54690732373, 140022269235

Offset

1,1

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) + a(n-4) -a (n-5).

Empirical g.f.: x*(3 - x^2)*(1 + x^2) / (1 - 3*x + 2*x^2 - 2*x^3 - x^4 + x^5). - Colin Barker, Sep 06 2018

Example

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

Crossrefs

Column 1 of A226852.

Sequence in context: A292329 A133654 A193695 * A096574 A045650 A191342

Adjacent sequences: A226842 A226843 A226844 * A226846 A226847 A226848

Keyword

nonn

Author

R. H. Hardin, Jun 19 2013

Status

approved