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A243471
Primes p such that p^6 - p^5 + 1 is prime.
2
3, 31, 73, 181, 367, 373, 523, 631, 733, 1021, 1039, 1171, 1489, 1723, 1777, 2203, 2557, 2683, 3121, 3187, 3319, 4441, 4591, 4621, 4801, 4957, 5113, 5167, 5323, 5431, 5659, 5839, 5851, 5857, 6883, 7057, 7129, 7297, 7309, 7477, 7993, 8017, 8209, 8221, 8689, 8821
OFFSET
1,1
LINKS
EXAMPLE
31 appears in the sequence because it is prime and 31^6 - 31^5 + 1 = 858874531 is also prime.
73 appears in the sequence because it is prime and 73^6 - 73^5 + 1 = 149261154697 is also prime.
MAPLE
A243471 := proc() local a, b; a:=ithprime(n); b:= a^6-a^5+1; if isprime (b) then RETURN (a); fi; end: seq(A243471 (), n=1..2000);
MATHEMATICA
c=0; Do[k=Prime[n]; If[PrimeQ[k^6-k^5+1], c++; Print[c, " ", k]], {n, 1, 200000}];
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Jun 05 2014
STATUS
approved