login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A095912 Variant of the pay-phone sequence A095236. Here a slot at the end of the row is always preferred over a slot sandwiched immediately between two used slots. 1
1, 2, 4, 6, 12, 28, 104, 152, 528, 2208, 9120, 23616, 130944, 278784, 1635840, 14181120, 32186880, 116674560, 1262039040, 2443714560, 58920099840, 161981890560, 1416311930880, 7700720025600, 120779469619200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

Example: there are 5 payphones. First arrival may choose any; he selects phone #2. Next arrival must take the furthest away, #5. Next arrival must take either of #3 or #4 (since both have a neighbor on one side and a vacant slot on the other); he chooses #3. Next arrival must take #1 (because end slots are preferred over "sandwiched" slots), leaving #4 for the last arrival. The permutation (25314) is one of a(5)=10 that satisfy the requirements.

CROSSREFS

Cf. A095236, A095239, A095240, A095923.

Sequence in context: A087997 A177905 A118405 * A143474 A220423 A087902

Adjacent sequences:  A095909 A095910 A095911 * A095913 A095914 A095915

KEYWORD

nonn

AUTHOR

Jon Wild, Jul 13 2004

EXTENSIONS

Corrected and extended by Don Reble (djr(AT)nk.ca), Jul 15 2004

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified November 28 05:47 EST 2014. Contains 250286 sequences.