A258893 Number of (n+2) X (7+2) 0..1 arrays with no 3 X 3 subblock diagonal sum less than the antidiagonal sum or central row sum less than the central column sum.

271350, 104329, 33252, 17424, 21320, 26244, 32400, 40000, 49288, 60516, 74000, 90000, 108936, 131044, 156880, 186624, 221000, 260100, 304848, 355216, 412360, 476100, 547856, 627264, 716040, 813604, 922000, 1040400, 1171208, 1313316

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) - 6*a(n-3) + 6*a(n-5) - 2*a(n-6) - 2*a(n-7) + a(n-8) for n > 11.

Empirical for n mod 2 = 0: a(n) = n^4 + 10*n^3 + 217*n^2 + 960*n + 9216 for n > 3.

Empirical for n mod 2 = 1: a(n) = n^4 + 10*n^3 + 218*n^2 + 946*n + 9265 for n > 3.

Empirical g.f.: x*(271350 - 438371*x - 718106*x^2 + 1370362*x^3 + 545942*x^4 - 1479832*x^5 - 41458*x^6 + 602478*x^7 - 38780*x^8 - 54557*x^9 - 18836*x^10) / ((1 - x)^5*(1 + x)^3). - Colin Barker, Dec 23 2018

Example

Some solutions for n=1:
  0 0 1 0 0 1 0 0 0      1 0 0 0 0 0 1 0 0
  1 1 1 1 1 1 1 1 0      1 0 1 1 1 1 0 1 0
  0 0 1 0 1 1 1 0 1      0 0 0 0 0 0 1 0 1

Crossrefs

Column 7 of A258894.

Sequence in context: A206001 A244561 A137715 * A237181 A013998 A236623

Adjacent sequences: A258890 A258891 A258892 * A258894 A258895 A258896

Keyword

nonn

Author

R. H. Hardin, Jun 14 2015

Status

approved