A267487 - OEIS

A267487

Primes p such that A001221(p+1)^(p-1) == 1 (mod p^2).

2, 3, 7, 31, 127, 1093, 3511, 8191, 131071, 524287

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OFFSET

1,1

COMMENTS

No further terms up to 10^9.

Are all terms of A000668 and A001220 in the sequence?

Does the sequence contain any terms not in A000668 or A001220 other than 2?

LINKS

MAPLE

isA267487 := proc(p)

if isprime(p) then

A001221(p+1) ;

simplify(modp(% &^ (p-1), p^2) =1 );

else

false;

end if;

end proc:

p := 2;

for i from 1 do

if isA267487(p) then

printf("%d\n", p) ;

end if;

p := nextprime(p) ;

end do: # R. J. Mathar, Jan 23 2016

MATHEMATICA

Select[Prime[Range[3200]], Mod[PrimeNu[# + 1], #^2]^(# - 1) == 1 &] (* G. C. Greubel, Apr 25 2017 *)

PROG

(PARI) forprime(p=1, 1e9, if(Mod(omega(p+1), p^2)^(p-1)==1, print1(p, ", ")))

CROSSREFS

KEYWORD

nonn,more

AUTHOR

STATUS

approved