A235838 Number of (n+1)X(1+1) 0..2 arrays with the sum of each 2X2 subblock two extreme terms minus its two median terms lexicographically nondecreasing rowwise and columnwise

81, 487, 2581, 12373, 55929, 241933, 1015889, 4174941, 16895401, 67647573, 268781649, 1062687069, 4187377529, 16469997477, 64715520737, 254249916141, 999126102153, 3928936941941, 15463007464305, 60919637465405

Offset

1,1

Comments

Column 1 of A235842

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -204*a(n-3) +368*a(n-4) +1728*a(n-5) -4720*a(n-6) -6672*a(n-7) +25984*a(n-8) +10560*a(n-9) -74880*a(n-10) +1920*a(n-11) +116160*a(n-12) -24000*a(n-13) -89600*a(n-14) +19200*a(n-15) +25600*a(n-16)

Example

Some solutions for n=5
..2..1....2..2....1..2....2..0....2..0....1..0....0..1....1..0....0..2....2..2
..2..0....1..0....2..1....2..2....1..2....1..2....1..2....0..1....2..0....0..1
..2..1....1..2....1..2....1..2....2..1....2..1....1..0....1..0....0..2....1..0
..0..1....0..0....0..1....2..1....1..0....1..2....1..0....1..2....2..0....1..2
..2..1....0..1....0..0....1..0....2..0....1..0....0..2....0..0....1..1....1..2
..1..2....2..0....1..2....2..0....1..0....2..1....0..1....0..1....2..2....0..1

Crossrefs

Sequence in context: A205239 A236427 A235842 * A304617 A205206 A205063

Adjacent sequences: A235835 A235836 A235837 * A235839 A235840 A235841

Keyword

nonn

Author

R. H. Hardin, Jan 16 2014

Status

approved