login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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. 1
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 25 22:55 EST 2020. Contains 332270 sequences. (Running on oeis4.)