A064936 Primes p such that gcd(p, prime(p)^2 - 1) does not equal 1.

2, 3, 5, 181, 40087, 251737

Offset

1,1

Comments

No further terms up to 41161739. - Harvey P. Dale, Dec 23 2011

No further terms up to 250000000. - Sean A. Irvine, Aug 01 2023

Links

Table of n, a(n) for n=1..6.

Example

5 belongs in the sequence because gcd(5, P_5^2 -1) = gcd(5, 120) = 5.

Mathematica

Do[ If[ GCD[ Prime[n], Prime[ Prime[n]]^2 - 1] != 1, Print[ Prime[n]] ], {n, 1, 10^6} ]

Crossrefs

Cf. A064830.

Sequence in context: A366642 A319609 A140551 * A041655 A082520 A062597

Adjacent sequences: A064933 A064934 A064935 * A064937 A064938 A064939

Keyword

nonn,more

Author

Robert G. Wilson v, Oct 26 2001

Status

approved