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A263309
Numbers n such that p=6n+1 and q=6p+1 are primes.
2
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
1,2
COMMENTS
Subsequence of A024899.
The subsequence of primes in this sequence is A023256.
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]&]
PROG
(PARI) isok(n) = isprime(p=6*n+1) && isprime(6*p+1); \\ Michel Marcus, Oct 17 2015
CROSSREFS
Sequence in context: A189395 A190003 A357702 * A253913 A190789 A373049
KEYWORD
nonn
AUTHOR
Zak Seidov, Oct 13 2015
STATUS
approved