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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A141218 Nonprimes of the form ((p(max)-1)*..*p*(p(min)+1)), where a(0)=1 and (p(max))*..*p*(p(min)=k(n)=n-th nonprime. 3
1, 6, 6, 8, 12, 12, 18, 16, 12, 18, 24, 24, 30, 24, 24, 36, 24, 36, 36, 24, 40, 48, 36, 36, 54, 48, 48, 54, 60, 48, 66, 48, 48, 60, 64, 72, 54, 60, 72, 72, 84, 72, 90, 72, 48, 72, 90, 96, 88, 90, 72, 108, 80, 108, 80, 108, 96, 72, 120, 108, 96, 126, 112, 120, 108, 96, 132, 120 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

If k(1)=4=(p(max)=2)*(p(min)=2), then (2-1)*(2+1)=1*3=3

(prime).

If k(2)=6=(p(max)=3)*(p(min)=2), then

(3-1)*(2+1)=2*3=6 (nonprime)=a(1).

If k(3)=8=(p(max)=2)*(p=2)*(p(min)=2), then

(2-1)*2*(2+1)=1*2*3=6 (nonprime)=a(2), etc.

CROSSREFS

Sequence in context: A195707 A175217 A000509 * A160257 A183042 A083507

Adjacent sequences:  A141215 A141216 A141217 * A141219 A141220 A141221

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov Aug 7 2008

EXTENSIONS

a(27), a(41), a(53) corrected by R. J. Mathar, Aug 18 2008

STATUS

approved

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

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

Last modified May 25 23:56 EDT 2013. Contains 225650 sequences.