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 A238083 Primes p such that p^4 - p^3 + 1 is also prime. 1
 67, 139, 337, 409, 577, 607, 631, 1297, 1321, 1429, 1459, 1549, 1627, 2377, 2557, 2767, 2851, 2917, 3001, 3187, 3319, 3499, 4027, 4099, 4621, 4861, 4969, 5059, 5431, 5449, 5581, 5827, 5857, 6007, 6037, 6379, 6481, 6781, 6997, 7411, 7927, 8089, 8191, 8311 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS K. D. Bajpai, Table of n, a(n) for n = 1..3409 EXAMPLE 67 is in the sequence because 67 is prime and 67^4 - 67^3 + 1 = 19850359 is also prime. 337 is in the sequence because 337 is prime and 337^4 - 337^3 + 1 = 12859645009 is also prime. MAPLE KD := proc() local a, b;  a:= ithprime(n);  b:= a^4 - a^3 + 1;  if isprime(b) then RETURN (a); fi; end: seq(KD(), n=1..2000); MATHEMATICA c=0; a=2; Do[k=Prime[n];  If[PrimeQ[k^4-k^3+1], c=c+1;  Print[c, " ", k]],    {n, 1, 100000}]; PROG (PARI) isok(p) = isprime(p) && isprime(p^4 - p^3 + 1); \\ Michel Marcus, Feb 27 2014 CROSSREFS Cf. A000040, A237639, A237641, A237642. Sequence in context: A106755 A320876 A304383 * A118200 A163303 A259956 Adjacent sequences:  A238080 A238081 A238082 * A238084 A238085 A238086 KEYWORD nonn AUTHOR K. D. Bajpai, Feb 17 2014 EXTENSIONS More terms from Michel Marcus, Feb 27 2014 STATUS approved

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Last modified June 18 17:05 EDT 2019. Contains 324214 sequences. (Running on oeis4.)