login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A235948
Number of (n+1) X (2+1) 0..2 arrays colored with the upper median value of each 2 X 2 subblock.
1
294, 722, 1372, 2660, 5034, 9752, 18468, 35794, 67924, 131474, 251786, 485354, 926434, 1789970, 3433586, 6602990, 12649018, 24390182, 46809866, 89947622, 172622482, 332388566, 638104130, 1225937510, 2354814226, 4530138566
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-3) + 10*a(n-4) - 12*a(n-7) - 6*a(n-8) for n>12.
Empirical g.f.: 2*x*(147 + 361*x + 686*x^2 + 889*x^3 - 36*x^4 - 792*x^5 - 1616*x^6 - 1190*x^7 - 622*x^8 - 327*x^9 - 62*x^10 + 5*x^11) / (1 - 3*x^3 - 10*x^4 + 12*x^7 + 6*x^8). - Colin Barker, Oct 20 2018
EXAMPLE
Some solutions for n=5:
..0..2..1....1..0..0....1..0..0....2..0..1....1..2..2....2..2..1....1..2..1
..2..1..0....2..1..0....1..0..1....1..2..0....0..0..2....0..0..0....2..1..0
..0..0..0....1..2..0....0..0..2....0..1..2....1..0..1....2..1..0....0..0..0
..0..1..2....0..0..0....2..1..2....0..0..0....2..0..0....1..2..1....0..1..2
..1..2..1....0..2..1....2..0..0....2..1..0....2..1..2....0..0..2....0..2..1
..2..1..0....1..0..2....1..1..0....2..1..0....1..0..2....0..1..0....2..1..0
CROSSREFS
Column 2 of A235954.
Sequence in context: A367207 A255104 A212724 * A250752 A235007 A235002
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2014
STATUS
approved