A106041 Numbers n such that n*prime(n)-1 is a perfect square.

1, 10, 50, 4946, 397706, 1243141, 3445873, 9210805, 805715770, 1542576890

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 * A370737 A264044 A143855

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