A234770 Number of (n+1) X (1+1) 0..4 arrays with 2 X 2 edge jumps all no more than +1 in one of the clockwise or counterclockwise directions but not both.

88, 454, 2056, 10076, 46804, 226072, 1060636, 5086576, 23991808, 114597900, 542168944, 2583725396, 12245147680, 58277217168, 276473917972, 1314790543248, 6241143226396, 29667097057792, 140873066386336, 669466007785964

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 21*a(n-2) - a(n-3) - 67*a(n-4) - 10*a(n-5) + 46*a(n-6).

Empirical g.f.: 2*x*(44 + 183*x - 123*x^2 - 713*x^3 - 49*x^4 + 513*x^5) / (1 - x - 21*x^2 + x^3 + 67*x^4 + 10*x^5 - 46*x^6). - Colin Barker, Oct 16 2018

Example

Some solutions for n=5:
..1..3....1..2....1..1....1..3....2..0....4..4....4..4....2..2....3..2....0..2
..2..2....1..0....2..3....2..3....2..1....2..3....3..2....4..3....3..4....0..1
..0..1....2..3....2..1....1..0....2..3....2..4....1..1....1..2....2..1....2..2
..2..1....1..0....0..0....1..2....4..3....2..3....2..0....1..3....0..1....1..3
..3..4....2..2....2..1....0..0....1..2....2..1....1..1....1..2....0..2....2..3
..2..2....1..0....3..0....1..2....3..3....3..4....2..0....0..2....1..2....4..4

Crossrefs

Column 1 of A234777.

Sequence in context: A064022 A116065 A234777 * A052049 A046378 A187176

Adjacent sequences: A234767 A234768 A234769 * A234771 A234772 A234773

Keyword

nonn

Author

R. H. Hardin, Dec 30 2013

Status

approved