A234382 Number of (2+2) X (n+2) 0..2 arrays with no increasing sequence of length 3 vertically, diagonally downwards or antidiagonally downwards.

372690, 24485940, 1622352843, 107611542837, 7134211462374, 472916732993424, 31349931916914819, 2078226021454554393, 137767978973627782722, 9132789623227746008508, 605422624854683742473907, 40134131167015140040092141, 2660535661387470166634276214, 176369832095419033605926212680

Offset

1,1

Links

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

Formula

Empirical: a(n) = 75*a(n-1) -428*a(n-2) -12080*a(n-3) +258675*a(n-4) -7798857*a(n-5) +2365290*a(n-6) +914935626*a(n-7) -1993096944*a(n-8) -10795294656*a(n-9) +17418530520*a(n-10) -1096243801776*a(n-11) +2225035316448*a(n-12) +21748340420928*a(n-13) -10024441535232*a(n-14) +287526368342016*a(n-15) -771748427870208*a(n-16) -7161694184521728*a(n-17) +2017438966628352*a(n-18) -237809116643328*a(n-19) +37432575963168768*a(n-20) +333658310974636032*a(n-21) -77998046721343488*a(n-22) -623984373770747904*a(n-23).

Example

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

Crossrefs

Row 2 of A234380.

Sequence in context: A219284 A017537 A234792 * A178288 A384346 A390436

Adjacent sequences: A234379 A234380 A234381 * A234383 A234384 A234385

Keyword

nonn

Author

R. H. Hardin, Dec 25 2013

Extensions

Name corrected by Andrew Howroyd, Mar 20 2025

Status

approved