[go: up one dir, main page]

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”).

A234261
Number of (n+1) X (3+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).
1
104, 170, 292, 560, 1100, 2324, 4924, 10988, 24284, 56060, 127132, 300380, 693020, 1664924, 3887644, 9452828, 22260764, 54595100, 129337372, 319132700, 759181340, 1881143324, 4487847964, 11152445468, 26658390044, 66377408540, 158876074012
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 6*a(n-2) - 24*a(n-3) + 4*a(n-4) + 36*a(n-5) - 24*a(n-6).
Empirical g.f.: 2*x*(52 - 71*x - 421*x^2 + 580*x^3 + 666*x^4 - 876*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 14 2018
EXAMPLE
Some solutions for n=5:
0 0 2 1 1 0 1 1 2 0 2 0 2 0 0 2 0 2 0 2
2 0 0 1 0 1 0 2 0 0 0 0 2 2 0 0 0 0 0 0
0 0 2 1 1 0 1 1 2 0 2 0 2 0 0 2 0 2 0 2
2 0 0 1 0 1 0 2 1 1 1 1 2 2 0 0 2 2 2 2
0 0 2 1 2 1 2 2 0 2 0 2 2 0 0 2 2 0 2 0
2 0 0 1 0 1 0 2 1 1 1 1 2 2 0 0 0 0 0 0
CROSSREFS
Column 3 of A234266.
Sequence in context: A253693 A168528 A259767 * A260288 A044336 A044717
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2013
STATUS
approved