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A053704 Prime powers p^w (w >= 2) such that p^w-2 is prime. 1
4, 9, 25, 49, 81, 169, 243, 361, 729, 841, 1369, 1849, 2209, 2401, 3721, 5041, 6859, 7921, 10609, 11449, 14641, 16129, 17161, 19321, 19683, 28561, 29791, 29929, 36481, 44521, 49729, 50653, 54289, 57121, 66049, 85849, 97969, 113569, 128881 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

FORMULA

A025475(n) - 2 is prime

EXAMPLE

4 is here since 4-2=2, 243=3^5 is here because 241 is prime

MATHEMATICA

Select[Range[130000], !PrimeQ[#]&&PrimePowerQ[#]&&PrimeQ[#-2]&] (* Harvey P. Dale, Oct 07 2020 *)

CROSSREFS

A025475.

Sequence in context: A336230 A130283 A065739 * A277900 A344701 A182988

Adjacent sequences:  A053701 A053702 A053703 * A053705 A053706 A053707

KEYWORD

nonn

AUTHOR

Labos Elemer, Feb 14 2000

EXTENSIONS

Definition clarified by Harvey P. Dale, Oct 07 2020

STATUS

approved

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Last modified August 5 15:11 EDT 2021. Contains 346471 sequences. (Running on oeis4.)