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 A075548 Perfect powers n such that (n-17)/2 is prime. 1
 27, 243, 343, 19683, 29791, 300763, 421875, 493039, 658503, 759375, 1367631, 2048383, 2685619, 3176523, 4019679, 5000211, 8869743, 9393931, 15069223, 17373979, 19034163, 25672375, 32461759, 43243551, 52734375, 54439939, 63521199, 82312875, 84604519 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Charlie Neder, Table of n, a(n) for n = 1..865 EXAMPLE a(1)=3^3, a(2)=3^5, a(3)=7^3, a(4)=3^9, a(5)=31^3, a(6)=67^3, a(7)=75^3, a(8)=79^3, a(9)=87^3, a(10)=15^5, a(11)=111^3, a(12)=127^3, a(13)=139^3, a(14)=147^3, a(15)=159^3, a(16)=171^3, a(17)=207^3 and a(18)=211^3. MATHEMATICA pp = Join[{1}, Select[ Range[10^7], Apply[GCD, Last[ Transpose[ FactorInteger[ # ]]]] > 1 & ]]; Select[pp, PrimeQ[(# - 17)/2] & ] Select[Flatten[Table[n^Range[2, 10], {n, 250}]], PrimeQ[(#-17)/2]&]//Union (* Harvey P. Dale, Dec 08 2018 *) CROSSREFS Sequence in context: A069979 A183806 A207104 * A074117 A030509 A042414 Adjacent sequences:  A075545 A075546 A075547 * A075549 A075550 A075551 KEYWORD easy,nonn AUTHOR Zak Seidov, Oct 11 2002 EXTENSIONS Extended by Robert G. Wilson v, Oct 14 2002 a(19)-a(29) from Charlie Neder, Feb 11 2019 STATUS approved

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Last modified August 5 22:11 EDT 2020. Contains 336214 sequences. (Running on oeis4.)