A258890 Number of (n+2) X (4+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.

10201, 10680, 8100, 7225, 9604, 13221, 17424, 23393, 30276, 39565, 50176, 63945, 79524, 99125, 121104, 148081, 178084, 214173, 254016, 301145, 352836, 413125, 478864, 554625, 636804, 730541, 831744, 946153, 1069156, 1207125, 1354896

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 + 122*n^2 + 498*n + 2385 for n>3.

Empirical for n mod 2 = 1: a(n) = n^4 + 10*n^3 + 121*n^2 + 480*n + 2304 for n>3.

Empirical g.f.: x*(10201 - 9722*x - 33662*x^2 + 30871*x^3 + 43034*x^4 - 33043*x^5 - 28554*x^6 + 12889*x^7 + 11977*x^8 - 883*x^9 - 2916*x^10) / ((1 - x)^5*(1 + x)^3). - Colin Barker, Dec 22 2018

Example

Some solutions for n=4:
..0..1..0..0..0..1....0..1..0..1..0..1....1..0..0..0..0..0....1..0..1..0..0..1
..1..1..0..1..0..0....1..1..1..1..1..0....1..0..0..0..0..0....1..1..0..1..0..1
..1..0..1..0..1..1....1..1..1..1..1..1....0..0..0..0..0..1....1..0..1..0..1..1
..1..1..0..1..0..1....1..1..1..1..1..1....0..0..0..0..0..0....0..1..0..1..0..1
..1..0..1..0..1..1....0..1..1..1..1..1....0..0..0..0..0..1....0..0..1..0..1..1
..0..1..0..1..0..1....1..0..1..1..1..1....0..0..0..0..0..1....0..0..0..0..1..1

Crossrefs

Column 4 of A258894.

Sequence in context: A221119 A105582 A243819 * A255872 A291925 A255880

Adjacent sequences: A258887 A258888 A258889 * A258891 A258892 A258893

Keyword

nonn

Author

R. H. Hardin, Jun 14 2015

Status

approved