A137839 Least prime P such that 3*p(n)*P*(3*p(n)*P+1)-1, 3*p(n)*P*(3*p(n)*P+1)+1,3*p(n)*P*(3*p(n)*P+3)-1,3*p(n)*P*(3*p(n)*P+3)+1 are all primes with p(i) = i-th prime.

3109, 14537, 5879, 79, 6203, 22307, 12569, 2749, 2647, 2767, 15061, 33713, 64693, 420851, 12743, 125941, 119179, 640771, 171329, 75793, 58027, 7, 129341, 4409, 10093, 18301, 21817, 7253, 58109, 4271, 86599, 211723, 7703, 238339, 90437, 136991, 13619, 1607, 4639

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Maple

f:= proc(p) local k;
  k:= 1:
  do
    k:= nextprime(k);
    if isprime(3*p*k*(3*p*k+1)-1) and
       isprime(3*p*k*(3*p*k+1)+1) and
       isprime(3*p*k*(3*p*k+3)-1) and
       isprime(3*p*k*(3*p*k+3)+1) then return k
    fi
  od
end proc:
map(f, [seq(ithprime(i), i=1..50)]); # Robert Israel, Jan 04 2021

Crossrefs

Sequence in context: A257356 A187593 A230923 * A343373 A238513 A357957

Adjacent sequences: A137836 A137837 A137838 * A137840 A137841 A137842

Keyword

nonn

Author

Pierre CAMI, Apr 29 2008

Extensions

Corrected and extended by D. S. McNeil, Dec 10 2010

Status

approved