A075547 Perfect powers n such that (n-13)/2 is prime.

27, 1331, 2187, 250047, 759375, 2460375, 12326391, 13651919, 20796875, 33698267, 51064811, 52734375, 63521199, 80062991, 86938307, 139798359, 156590819, 170953875, 190109375, 219256227, 377933067, 502459875, 625026375, 642735647, 679151439, 707347971, 756058031, 985074875

Offset

1,1

Comments

27=3^3, 1331=11^3, 2187=3^7, 250047=63^3, 759375=15^5 and 2460375=135^3.

Links

Charlie Neder, Table of n, a(n) for n = 1..496

Mathematica

pp = Join[{1}, Select[ Range[10^7], Apply[GCD, Last[ Transpose[ FactorInteger[ # ]]]] > 1 & ]]; Select[pp, PrimeQ[(# - 13)/2] & ]

Crossrefs

Sequence in context: A163568 A066300 A273518 * A167732 A017103 A042407

Adjacent sequences: A075544 A075545 A075546 * A075548 A075549 A075550

Keyword

easy,nonn

Author

Zak Seidov, Oct 11 2002

Extensions

Extended by Robert G. Wilson v, Oct 14 2002

a(7)-a(28) from Charlie Neder, Feb 11 2019

Status

approved