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 A233512 The first n cyclotomic polynomials are simultaneously prime for these arguments. 1
 3, 4, 6, 150, 1068630, 6770610 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The first six cyclotomic polynomials are x - 1, x + 1, x^2 + x + 1, x^2 + 1, x^4 + x^3 + x^2 + x + 1, and x^2 - x + 1. By Schinzel's hypothesis H, this sequence is defined for all n. a(7) > 2*10^9. REFERENCES See A087277. LINKS EXAMPLE At x = 3, x-1 = 2, which is prime. At x = 4, x-1 = 3 and x+1 = 5, which are both prime. At x = 6, x-1 = 5, x+1 = 7, and x^2+x+1 = 43, which are all prime. MATHEMATICA t = {}; n = 0; len = 0; While[len < 6, n++; found = True; i = 1; While[found && i <= len + 1, found = PrimeQ[Cyclotomic[i, n]]; i++]; If[found && i > len + 1, AppendTo[t, n]; len++]]; t CROSSREFS Cf. A014574 (first degree solutions: average of twin primes). Cf. A087277 (similar, but with second-degree cyclotomic polynomials). Cf. A231612 (similar, but with fourth-degree cyclotomic polynomials). Cf. A231613 (similar, but with sixth-degree cyclotomic polynomials). Cf. A231614 (similar, but with eighth-degree cyclotomic polynomials). Sequence in context: A066466 A332511 A129293 * A095877 A024476 A173014 Adjacent sequences:  A233509 A233510 A233511 * A233513 A233514 A233515 KEYWORD nonn,hard,more AUTHOR T. D. Noe, Dec 13 2013 STATUS approved

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Last modified July 5 23:36 EDT 2020. Contains 335475 sequences. (Running on oeis4.)