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

 

Logo

110 people attended OEIS-50 (videos, suggestions); annual fundraising drive to start soon (donate); editors, please edit! (stack is over 300), your editing is more valuable than any donation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A048243 Number of non-unitary divisors of C(n,[ n/2 ]) = A000005[ n ] - A034444[ n ]. 4
0, 0, 0, 0, 0, 2, 0, 0, 4, 10, 0, 8, 8, 16, 8, 16, 0, 16, 0, 16, 32, 64, 0, 32, 80, 128, 224, 320, 256, 352, 64, 128, 256, 512, 256, 640, 640, 1024, 512, 1280, 512, 1024, 512, 1024, 2560, 3328, 1280, 2432, 2432, 3584, 3584, 5120, 2048, 2816, 2048, 4096, 8192 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

At n=10, he C(10,5) = 252=4*9*7 has 18 divisors, 8 are unitary and the residual 10 are non-unitary; thus a[ 10 ]=10=18-8.

CROSSREFS

A048105 applied to terms of A001405.

Sequence in context: A197007 A011449 A231037 * A159814 A169774 A057611

Adjacent sequences:  A048240 A048241 A048242 * A048244 A048245 A048246

KEYWORD

nonn

AUTHOR

Labos Elemer

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 1 03:30 EDT 2014. Contains 248887 sequences.