A347032 Primes that are of the form p^k-2 for some k > 3 and prime p.

79, 241, 727, 2399, 14639, 19681, 28559, 371291, 707279, 823541, 1771559, 2825759, 3418799, 5764799, 7890479, 12117359, 24137567, 28398239, 28629149, 47458319, 104060399, 1073283119, 2565726407, 3262808639, 3373402559, 5887339439, 6103515623, 7370050799, 9354951839, 10779215327, 13841287199

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Example

a(3) = 727 is a term because 727 = 3^6-2, 6 > 3 and 727 and 3 are prime.

Maple

N:= 10^12: # for terms <= N
R:= {}:
p:= 1:
do
  p:= nextprime(p);
  if p^4-2 > N then break fi;
  for k from 4 to ilog[p](N) do
     r:= p^k - 2;
     if isprime(r) then R:= R union {r} fi;
  od
od:
sort(convert(R, list));

Prog

(PARI) isok(p) = isprime(p) && (isprimepower(p+2) > 3); \\ Michel Marcus, Aug 16 2021

Crossrefs

Sequence in context: A257933 A258098 A141964 * A142285 A265599 A076815

Adjacent sequences: A347029 A347030 A347031 * A347033 A347034 A347035

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Aug 11 2021

Status

approved