login
A224991
Primes p such that q=2*p^2-1, r=2*p*q-1 and 2*p*r-1 are also prime.
1
181, 32341, 52021, 96907, 97171, 100981, 109507, 192601, 194671, 238237, 280627, 304651, 320911, 418321, 449971, 547537, 579961, 626191, 668611, 767857, 769807, 771091, 806107, 885097, 954157, 991381, 993247, 1028047, 1075357, 1259677, 1285021, 1368727, 1414837, 1415191, 1425007, 1449841
OFFSET
1,1
COMMENTS
Subsequence of A224990, and more elementary version of A224626.
LINKS
MATHEMATICA
qr[p_]:=Module[{q=2p^2-1, r}, r=2p*q-1; {q, r, 2p*r-1}]; Select[Prime[ Range[ 120000]], AllTrue[qr[#], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 10 2015 *)
PROG
(PARI) forprime(p=1, 2e6, isprime(q=2*p^2-1)&&isprime(r=2*p*q-1)&&isprime(2*p*r-1)&&print1(p", "))
CROSSREFS
Sequence in context: A226714 A083979 A179408 * A189342 A189778 A322904
KEYWORD
nonn
AUTHOR
M. F. Hasler, Apr 22 2013
STATUS
approved