A253494 Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

48293, 51167, 60586, 82676, 127898, 220988, 415106, 827156, 1722698, 3728108, 8381906, 19618436, 47878298, 121758428, 321599906, 877526516, 2458110698, 7025471948, 20378773106, 59741111396, 176432995898, 523718388668

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..149

Formula

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

Empirical: a(n) = 49*3^(n-1) + 5322*2^(n-1) + 38777 for n>3.

Empirical g.f.: x*(48293 - 238591*x + 284807*x^2 - 7761*x^3 - 8714*x^4 - 480*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)). - Colin Barker, Dec 16 2018

Example

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

Crossrefs

Column 7 of A253495.

Sequence in context: A186592 A221556 A227701 * A253501 A253455 A233890

Adjacent sequences: A253491 A253492 A253493 * A253495 A253496 A253497

Keyword

nonn

Author

R. H. Hardin, Jan 02 2015

Status

approved