A263309 Numbers k such that p=6k+1 and q=6k+1 are primes.

1, 2, 6, 10, 12, 17, 25, 30, 40, 45, 46, 47, 52, 55, 61, 62, 66, 96, 100, 101, 110, 121, 125, 131, 142, 151, 156, 172, 177, 186, 195, 200, 220, 221, 230, 237, 242, 255, 261, 282, 296, 305, 312, 331, 332, 356, 360, 367, 370, 380, 381, 382, 391, 425, 432, 446, 461, 465, 475, 495, 506, 510, 527, 530

Offset: 1

Author

Zak Seidov, Oct 13 2015

Keywords

• nonn

Comments

Subsequence of A024899.

The subsequence of primes in this sequence is A023256.

Crossrefs

Cf. A023256, A024899.

Programs

Maple

isA263309 := proc(n)
    if isprime(6*n+1) then
        if isprime(36*n+7) then
            true;
        else
            false;
        end if;
    else
        false;
    end if;
end proc:
for n from 1 to 100 do
    if isA263309(n) then
        printf("%d,",n);
    end if;
end do: # R. J. Mathar, Oct 17 2015

Mathematica

Select[Range[1000],PrimeQ[p=6*#+1]&& PrimeQ[q=6*p+1]&]

PARI

isok(n) = isprime(p=6*n+1) && isprime(6*p+1); \\ Michel Marcus, Oct 17 2015