OFFSET
1,1
COMMENTS
Terms k of A025475 such that k - 2 is prime.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A053705(n) + 2. - Amiram Eldar, Aug 27 2024
EXAMPLE
4 = 2^2 is a term since 4-2 = 2 is prime.
243 = 3^5 is a term because 241 is prime.
MATHEMATICA
Select[Range[130000], !PrimeQ[#]&&PrimePowerQ[#]&&PrimeQ[#-2]&] (* Harvey P. Dale, Oct 07 2020 *)
seq[max_] := Module[{s = {}, p = 2}, While[p^2 <= max, s = Join[s, Select[p^Range[2, Floor[Log[p, max]]], PrimeQ[# - 2] &]]; p = NextPrime[p]]; Union[s]]; seq[150000] (* Amiram Eldar, Aug 27 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Feb 14 2000
EXTENSIONS
Definition clarified by Harvey P. Dale, Oct 07 2020
STATUS
approved