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%I #9 Feb 11 2019 22:01:39
%S 27,1331,2187,250047,759375,2460375,12326391,13651919,20796875,
%T 33698267,51064811,52734375,63521199,80062991,86938307,139798359,
%U 156590819,170953875,190109375,219256227,377933067,502459875,625026375,642735647,679151439,707347971,756058031,985074875
%N Perfect powers n such that (n-13)/2 is prime.
%C 27=3^3, 1331=11^3, 2187=3^7, 250047=63^3, 759375=15^5 and 2460375=135^3.
%H Charlie Neder, <a href="/A075547/b075547.txt">Table of n, a(n) for n = 1..496</a>
%t pp = Join[{1}, Select[ Range[10^7], Apply[GCD, Last[ Transpose[ FactorInteger[ # ]]]] > 1 & ]]; Select[pp, PrimeQ[(# - 13)/2] & ]
%K easy,nonn
%O 1,1
%A _Zak Seidov_, Oct 11 2002
%E Extended by _Robert G. Wilson v_, Oct 14 2002
%E a(7)-a(28) from _Charlie Neder_, Feb 11 2019