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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A190064 Number of arrangements of n+1 nonzero numbers x(i) in -2..2 with the sum of div(x(i),x(i+1)), where div(a,b)=a/b produces the integer quotient implying a nonnegative remainder, equal to zero 1
2, 12, 40, 144, 550, 1896, 7584, 27328, 105348, 398760, 1538696, 5872800, 22646862, 87492676, 339055650, 1313842904, 5104724558, 19873572892, 77470783406, 302258087616, 1180840902336, 4618922848536, 18083348822516, 70852652846320 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A190071

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

EXAMPLE

Some solutions for n=4

.-2...-1...-1...-2...-2....1....2...-1...-1....2...-2....1....2....2....1....1

.-2....1....1...-1...-1...-1....1....1...-2...-1....1....1...-1....2...-2....1

..2....1...-2....1....1...-1....2....2....1...-2....1....2....2....2....1....1

.-2...-1....2....2...-2....2...-2...-2....1....2....1...-1....1...-2....2...-1

.-2...-2....1...-2....2....2....2...-1....2....1....2...-1....1....2....1....1

CROSSREFS

Sequence in context: A013194 A212874 A074447 * A240122 A110953 A003683

Adjacent sequences:  A190061 A190062 A190063 * A190065 A190066 A190067

KEYWORD

nonn

AUTHOR

R. H. Hardin May 04 2011

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 November 26 23:41 EST 2020. Contains 338670 sequences. (Running on oeis4.)