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A049092 Primes p such that p-1 is not squarefree. 5
5, 13, 17, 19, 29, 37, 41, 53, 61, 73, 89, 97, 101, 109, 113, 127, 137, 149, 151, 157, 163, 173, 181, 193, 197, 199, 229, 233, 241, 251, 257, 269, 271, 277, 281, 293, 307, 313, 317, 337, 349, 353, 373, 379, 389, 397, 401, 409, 421, 433, 449, 457, 461, 487 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p with mu(p-1)=0, where mu is the Möbius function. - T. D. Noe, Nov 03 2003

Primes p such that the sum of the primitive roots of p (see A088144) is 0 mod p. - Jon Wharf, Mar 12 2015

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

Eric Weisstein's World of Mathematics, Moebius Function

EXAMPLE

p=257 is here because p-1 = 256 = 2^8; p=997 is here because p-1 = 996 = 3*(2^2)*83.

MATHEMATICA

Select[Prime[Range[400]], MoebiusMu[ #-1]==0&]

PROG

(MAGMA) [ p: p in PrimesUpTo(500) | not IsSquarefree(p-1) ]; // Vincenzo Librandi, Mar 12 2015

(PARI) forprime(p=2, 500, if(!issquarefree(p-1), print(p))) \\ Michael B. Porter, Mar 16 2015

CROSSREFS

Cf. A078330 (primes p with mu(p-1)=-1), A088179 (primes p such that mu(p-1)=1), A089451 (mu(p-1) for prime p).

Sequence in context: A282747 A088908 A092218 * A103666 A082700 A212287

Adjacent sequences:  A049089 A049090 A049091 * A049093 A049094 A049095

KEYWORD

nonn

AUTHOR

Labos Elemer

STATUS

approved

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Last modified January 20 02:17 EST 2018. Contains 297938 sequences.