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 A258357 Numbers n such that cyclotomic polynomial value Phi(7,n!) is prime. 1
 0, 1, 2, 3, 13, 470, 2957 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Except for the values 0,1,2 and 3, terms correspond to probable primes. a(8) > 6502. Also, numbers n such that n! belongs to A100330. - Michel Marcus, May 30 2015 LINKS EXAMPLE 3 is in the sequence because Phi(7,3!) = 1 + 6 + 6^2 + 6^3 + 6^4 + 6^5 + 6^6 = 55987 is prime. MATHEMATICA Select[Range[0, 6502], PrimeQ[Cyclotomic[7, #!]] &] CROSSREFS Cf. A002981, A002982, A046029, A200906. Sequence in context: A090100 A270314 A132484 * A160858 A062648 A094003 Adjacent sequences:  A258354 A258355 A258356 * A258358 A258359 A258360 KEYWORD nonn,more AUTHOR Robert Price, May 27 2015 STATUS approved

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Last modified May 6 18:38 EDT 2021. Contains 343586 sequences. (Running on oeis4.)