OFFSET
1,1
COMMENTS
Numbers k of the form 2^a*3^b such that k-1 and (k-2)/2 are prime.
For all terms k except 6 and 8, k-2 is in A325204.
All terms except 6 and 12 end in 4 or 8.
LINKS
Ray Chandler, Table of n, a(n) for n = 1..39 (terms < 10^1000)
EXAMPLE
a(3)=12 is a term because 12=2^2*3 and 11 and 10/2 are prime.
MATHEMATICA
nmax = 10^35;
Select[Sort[Flatten[Table[2^i*3^j, {j, 0, Log[3, nmax]}, {i, Log[2, nmax/3^j]}]]], PrimeQ[# - 1] && PrimeQ[(# - 2)/2] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ray Chandler, Sep 14 2019
STATUS
approved