A258547 Number of (n+1)X(1+1) 0..1 arrays with every 2X2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically

16, 44, 104, 228, 480, 988, 2008, 4052, 8144, 16332, 32712, 65476, 131008, 262076, 524216, 1048500, 2097072, 4194220, 8388520, 16777124, 33554336, 67108764, 134217624, 268435348, 536870800, 1073741708, 2147483528, 4294967172

Offset

1,1

Comments

Column 1 and row 1 of A258554

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3)

a(n) = 16*2^n - 4*n - 12. - Michael Somos, Oct 14 2020

Example

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

Prog

(PARI) {a(n) = if(n<-2, 0, 16*2^n - 4*n - 12)}; /* Michael Somos, Oct 14 2020 */

Crossrefs

Cf. A258554

Sequence in context: A210375 A173560 A293858 * A211573 A211582 A204032

Adjacent sequences: A258544 A258545 A258546 * A258548 A258549 A258550

Keyword

nonn

Author

R. H. Hardin, Jun 03 2015

Status

approved