A232345 Number of (n+1)X(1+1) 0..2 arrays with every element both >= and <= some horizontal, vertical, diagonal or antidiagonal neighbor

21, 207, 1461, 10503, 77613, 575087, 4251717, 31416759, 232180893, 1716017023, 12682748597, 93735029639, 692772171789, 5120109604943, 37841480302757, 279677127167191, 2067025225364605, 15276877819722015, 112907667250391445

Offset

1,1

Comments

Column 1 of A232352

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -2*a(n-2) +30*a(n-3) +44*a(n-4) +8*a(n-5) +16*a(n-6) -32*a(n-7) -64*a(n-8).

Empirical: G.f.: x*(21+60*x+54*x^2+60*x^3-120*x^4-304*x^5-32*x^6+64*x^7) / ( 1 -7*x +2*x^2 -30*x^3 -44*x^4 -8*x^5 -16*x^6 +32*x^7 +64*x^8 ). - R. J. Mathar, Nov 24 2013

Example

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

Crossrefs

Sequence in context: A160769 A232352 A166190 * A036205 A160787 A226465

Adjacent sequences: A232342 A232343 A232344 * A232346 A232347 A232348

Keyword

nonn

Author

R. H. Hardin, Nov 22 2013

Status

approved