OFFSET
1,1
COMMENTS
Equivalently, these are the primes of form 2^(i+1)*3^j - 7. We empirically have log(a(n)) ~ 0.23...*n + O(1), but the constant seems difficult to compute precisely. - Matthew House, Aug 13 2024
LINKS
Matthew House, Table of n, a(n) for n = 1..9949 (all primes proven via ECPP)
MATHEMATICA
Select[Prime[Range[35000]], Divisible[#+7, EulerPhi[#+7]]&] (* Harvey P. Dale, Aug 15 2016 *)
lim = 10^7 + 7; Sort[Select[Flatten[Table[2^i*3^j - 7, {i, 1, Log2[lim]}, {j, 0, Log[3, lim/2^i]}]], # > 0 && PrimeQ[#] &]] (* Matthew House, Aug 13 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 22 2002
EXTENSIONS
More terms from Matthew House, Aug 13 2024
STATUS
approved