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A253976
Primes p such that (p^2 + 5)/6, (p^4 + 5)/6, (p^6 + 5)/6 and (p^8 + 5)/6 are prime.
4
67103, 7524593, 9938069, 10125793, 13042637, 55741139, 55792241, 58429099, 77618323, 92713879, 94554613, 96242761, 103774049, 119753549, 141725501, 142915193, 164899799, 165227399, 173202247, 174728233, 178411771, 184279409, 184356703, 186622003, 195863347, 200406977, 239488649
OFFSET
1,1
LINKS
Zak Seidov, Table of n, a(n) for n = 1..503 (all terms up to 10^10)
MATHEMATICA
Select[Prime[Range[132*10^5]], AllTrue[(#^Range[2, 8, 2]+5)/6, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 11 2018 *)
PROG
(PARI) forprime(p=1, 10^7, k=0; for(i=1, 4, P=(p^(2*i)+5)/6; if(P\1==P, if(ispseudoprime(P), k++); if(!ispseudoprime(P), k=0; break)); if(P\1!=P, k=0; break)); if(k, print1(p, ", "))) \\ Derek Orr, Jan 21 2015
CROSSREFS
Subsequence of A253939. Cf. A118915, A247478, A253939, A253940, A253941.
Sequence in context: A249193 A238068 A235892 * A237777 A251297 A251849
KEYWORD
nonn
AUTHOR
Zak Seidov, Jan 21 2015
STATUS
approved