A251928 Number of length n+2 0..1 arrays with the sum of the maximum minus the median of adjacent triples multiplied by some arrangement of +-1 equal to zero.

5, 10, 18, 34, 68, 136, 268, 528, 1048, 2088, 4160, 8288, 16528, 32992, 65888, 131616, 262976, 525568, 1050560, 2100224, 4199040, 8395904, 16788480, 33571840, 67135744, 134259200, 268499456, 536969728, 1073894400, 2147719168, 4295330816

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 6*a(n-3) - 4*a(n-4).

Empirical g.f.: x*(5 - 10*x + 8*x^2 - 8*x^3) / ((1 - 2*x)*(1 - 2*x + 2*x^2 - 2*x^3)). - Colin Barker, Dec 01 2018

Example

Some solutions for n=6:
..1....1....1....1....1....1....0....1....0....0....0....1....0....0....1....0
..1....0....0....0....1....1....0....1....1....1....1....1....0....1....1....1
..0....0....1....1....1....1....1....1....1....1....1....0....1....0....1....0
..0....0....1....0....0....1....0....1....0....0....1....0....0....1....1....1
..0....0....0....0....1....1....1....1....0....1....0....1....0....0....1....0
..0....0....0....1....1....0....0....0....1....1....1....0....1....0....1....0
..0....1....0....0....0....1....1....0....0....0....0....1....1....1....1....0
..1....1....1....1....1....1....0....1....0....1....0....0....1....1....0....1

Crossrefs

Column 1 of A251935.

Sequence in context: A058555 A226445 A296552 * A153370 A119135 A083287

Adjacent sequences: A251925 A251926 A251927 * A251929 A251930 A251931

Keyword

nonn

Author

R. H. Hardin, Dec 11 2014

Status

approved