A253835 Number of (n+2)X(2+2) 0..1 arrays with every 3X3 subblock diagonal sum plus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally

2440, 6339, 19970, 60741, 129378, 265117, 517697, 920743, 1570681, 2618604, 4231022, 6636278, 10253068, 15585443, 23416148, 34730393, 51160002, 74729961, 108671350, 156842600, 225956004, 324026686, 464035121, 661461991, 943337179

Offset

1,1

Comments

Column 2 of A253841

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +6*a(n-4) -12*a(n-5) +8*a(n-6) -4*a(n-7) -7*a(n-8) +18*a(n-9) -21*a(n-10) +24*a(n-11) -9*a(n-12) -6*a(n-13) +21*a(n-14) -36*a(n-15) +24*a(n-16) -12*a(n-17) -2*a(n-18) +16*a(n-19) -17*a(n-20) +18*a(n-21) -9*a(n-22) +4*a(n-24) -8*a(n-25) +4*a(n-26) for n>30

Example

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

Crossrefs

Sequence in context: A252047 A083625 A253842 * A253929 A233912 A233678

Adjacent sequences: A253832 A253833 A253834 * A253836 A253837 A253838

Keyword

nonn

Author

R. H. Hardin, Jan 16 2015

Status

approved