A235417 Number of (n+1)X(1+1) 0..2 arrays with 2X2 subblock sum of squares lexicographically nondecreasing rowwise and nonincreasing columnwise

81, 432, 2304, 9504, 39204, 138402, 488601, 1553877, 4941729, 14587326, 43059844, 120242088, 335768976, 898407396, 2403842841, 6218691273, 16087624569, 40503112884, 101972926224, 251077339656, 618201642564, 1494166176558

Offset

1,1

Comments

Column 1 of A235421

Links

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

Formula

Empirical: a(n) = 6*a(n-1) +12*a(n-2) -138*a(n-3) +44*a(n-4) +1362*a(n-5) -1706*a(n-6) -7446*a(n-7) +14669*a(n-8) +23808*a(n-9) -69362*a(n-10) -39576*a(n-11) +208600*a(n-12) -417200*a(n-14) +158304*a(n-15) +554896*a(n-16) -380928*a(n-17) -469408*a(n-18) +476544*a(n-19) +218368*a(n-20) -348672*a(n-21) -22528*a(n-22) +141312*a(n-23) -24576*a(n-24) -24576*a(n-25) +8192*a(n-26)

Example

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

Crossrefs

Sequence in context: A236698 A235421 A236282 * A237391 A237385 A237308

Adjacent sequences: A235414 A235415 A235416 * A235418 A235419 A235420

Keyword

nonn

Author

R. H. Hardin, Jan 10 2014

Status

approved