A233498 Number of (1+2)X(n+2) 0..2 arrays with no increasing sequence of length 3 horizontally or antidiagonally downwards.

16928, 388908, 8946936, 205862149, 4735554885, 108935413524, 2505862495421, 57642807090627, 1325965819487463, 30501379817750872, 701627499121212846, 16139635160671855638, 371262275177504806916, 8540197810102924672131

Offset

1,1

Comments

Row 1 of A233497

Links

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

Formula

Empirical: a(n) = 29*a(n-1) -84*a(n-2) -1570*a(n-3) +6618*a(n-4) +28026*a(n-5) -136815*a(n-6) -145173*a(n-7) +1005714*a(n-8) -486446*a(n-9) -1842056*a(n-10) +1805556*a(n-11) +1069186*a(n-12) -1763040*a(n-13) +27675*a(n-14) +626313*a(n-15) -148782*a(n-16) -66294*a(n-17) +19454*a(n-18) +2708*a(n-19) -849*a(n-20) -37*a(n-21) +12*a(n-22)

Example

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

Crossrefs

Sequence in context: A190935 A035922 A233497 * A233490 A233489 A205606

Adjacent sequences: A233495 A233496 A233497 * A233499 A233500 A233501

Keyword

nonn

Author

R. H. Hardin, Dec 11 2013

Status

approved