A339329 Primes p such that A001414(p-1)*A001414(p+1) == q (mod p), where q is the prime before p.

3, 13, 17, 29

Offset

1,1

Comments

Next term, if any, > 2*10^8.

Links

Table of n, a(n) for n=1..4.

Formula

a(n) = prime(k) where A339327(k) = prime(k-1).

Example

a(3)=17 is in the sequence because it is prime and A001414(16)*A001414(18) = 8*8 = 64 == 13 (mod 17), and 13 is the prime before 17.

Maple

spf:= n -> add(t[1]*t[2], t=ifactors(n)[2]):
p:= 1: R:= NULL:
while p < 10^7 do
  q:= p: p:= nextprime(p);
  v:= spf(p-1)*spf(p+1) mod p;
    if v = q then R:= R, p fi
od:
R;

Crossrefs

Cf. A001414, A339327

Sequence in context: A141188 A019347 A184777 * A045433 A216535 A356054

Adjacent sequences: A339326 A339327 A339328 * A339330 A339331 A339332

Keyword

nonn,bref,more

Author

Robert Israel, Nov 30 2020

Status

approved