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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106041 Numbers n such that n*prime(n)-1 is a perfect square. 2
1, 10, 50, 4946, 397706, 1243141, 3445873, 9210805, 805715770, 1542576890 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Next term, if it exists, is > 400000. - 397706 from Emeric Deutsch, May 31 2005

a(11) > pi(4*10^12). - Donovan Johnson, Oct 22 2010

a(11) > pi(1.9*10^14). - Giovanni Resta, May 21 2018

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

1*2-1=1^2

10*29-1=17^2

50*229-1=107^2

4946*47981-1=15405^2

CROSSREFS

Sequence in context: A216156 A072296 A143558 * A264044 A143855 A124162

Adjacent sequences:  A106038 A106039 A106040 * A106042 A106043 A106044

KEYWORD

nonn

AUTHOR

Zak Seidov, May 06 2005

EXTENSIONS

397706 from Emeric Deutsch, May 31 2005

4 more terms from Ryan Propper, Oct 16 2005

a(10) from Donovan Johnson, Oct 22 2010

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 August 20 01:14 EDT 2019. Contains 326136 sequences. (Running on oeis4.)