_R. H. Hardin (rhhardin(AT)att.net) _ Mar 15 2012

OEIS Server: https://oeis.org/edit/global/875

editing

approved

R. H. Hardin, <a href="/A209907/b209907.txt">Table of n, a(n) for n = 1..210</a>

allocatedHalf the number of (n+1)X3 0..3 arrays with every 2X2 subblock having two or four distinct forclockwise Ronedge Hardindifferences

562, 13098, 295448, 6711168, 152153160, 3452051294, 78298719958, 1776153151954, 40289004709802, 913904480044196, 20730591242525088, 470244787257936734, 10666837893533545782, 241962270764619764754, 5488573721848784927246

1,1

Column 2 of A209913

Empirical: a(n) = 16*a(n-1) +227*a(n-2) -1440*a(n-3) -8244*a(n-4) +46409*a(n-5) +53926*a(n-6) -406100*a(n-7) -117231*a(n-8) +1484559*a(n-9) +166049*a(n-10) -2587430*a(n-11) -386782*a(n-12) +2096907*a(n-13) +472125*a(n-14) -660956*a(n-15) -166954*a(n-16) +44616*a(n-17) +4488*a(n-18) -192*a(n-19)

Some solutions for n=4

..3..0..1....3..0..0....2..2..1....1..2..3....3..0..1....3..3..1....1..1..3

..2..0..3....1..1..3....3..0..2....2..3..1....1..3..0....1..0..3....0..3..0

..1..2..0....3..0..3....0..3..3....1..2..3....2..1..1....2..3..0....0..1..0

..2..0..3....2..0..1....1..0..2....3..1..2....1..3..0....1..2..1....0..3..1

..0..2..0....2..3..1....1..3..2....3..0..3....3..0..1....2..1..2....3..0..0

allocated

nonn

R. H. Hardin (rhhardin(AT)att.net) Mar 15 2012

approved

editing

allocated for Ron Hardin

allocated

approved