A234881 Number of (n+1) X (7+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 1, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

2048, 5684, 10240, 44540, 87312, 518988, 1035792, 7389460, 14782992, 115949340, 231949520, 1905124356, 3810241424, 31990186028, 63971965200, 542748911188, 1085288713808, 9254225370188, 18504385966768, 158172364558052

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) +77*a(n-2) -77*a(n-3) -2641*a(n-4) +2641*a(n-5) +53691*a(n-6) -53691*a(n-7) -725059*a(n-8) +725059*a(n-9) +6900779*a(n-10) -6900779*a(n-11) -47896812*a(n-12) +47896812*a(n-13) +247376416*a(n-14) -247376416*a(n-15) -961430772*a(n-16) +961430772*a(n-17) +2825059980*a(n-18) -2825059980*a(n-19) -6271823936*a(n-20) +6271823936*a(n-21) +10458154064*a(n-22) -10458154064*a(n-23) -12942372832*a(n-24) +12942372832*a(n-25) +11648212736*a(n-26) -11648212736*a(n-27) -7373325696*a(n-28) +7373325696*a(n-29) +3099131904*a(n-30) -3099131904*a(n-31) -774014976*a(n-32) +774014976*a(n-33) +86704128*a(n-34) -86704128*a(n-35).

Example

Some solutions for n=4:
  3 0 3 0 3 0 3 0      0 3 0 1 0 2 0 1      0 3 0 2 0 1 0 3
  4 2 4 2 4 2 4 2      2 4 2 4 2 3 2 4      2 4 2 3 2 4 2 4
  3 0 3 0 1 0 3 0      0 1 0 1 0 2 0 1      0 3 0 2 0 1 0 3
  4 2 4 2 4 2 4 2      2 4 2 4 2 3 2 4      2 4 2 3 2 4 2 4
  1 0 1 0 3 0 1 0      0 1 0 3 0 2 0 1      0 1 0 2 0 1 0 1

Crossrefs

Column 7 of A234882.

Sequence in context: A222526 A035892 A069272 * A220584 A195069 A316499

Adjacent sequences: A234878 A234879 A234880 * A234882 A234883 A234884

Keyword

nonn

Author

R. H. Hardin, Jan 01 2014

Status

approved