A267487 Primes p such that A001221(p+1)^(p-1) == 1 (mod p^2).

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

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

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

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

Cf. A000668, A001220, A260377.

Sequence in context: A228171 A089359 A239892 * A343733 A081947 A046972

Adjacent sequences: A267484 A267485 A267486 * A267488 A267489 A267490

Keyword

nonn,more

Author

Felix Fröhlich, Jan 15 2016

Status

approved