A258551 Number of (n+1) X (5+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.

480, 506, 1403, 2509, 5070, 8339, 12940, 18630, 26240, 35386, 46687, 59945, 76039, 94633, 116394, 141172, 169894, 202272, 239021, 280039, 326301, 377567, 434600, 497346, 566828, 642854, 726235, 816965, 916115, 1023541, 1140102, 1265840

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>13.

Empirical g.f.: x*(480 - 1414*x + 2259*x^2 - 1987*x^3 + 1428*x^4 - 579*x^5 - 888*x^6 + 1120*x^7 - 834*x^8 + 778*x^9 - 368*x^10 + 50*x^11 + 3*x^12) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 21 2018

Example

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

Crossrefs

Column 5 of A258554.

Sequence in context: A262222 A115157 A019287 * A257415 A179667 A108876

Adjacent sequences: A258548 A258549 A258550 * A258552 A258553 A258554

Keyword

nonn

Author

R. H. Hardin, Jun 03 2015

Status

approved