OFFSET
1,1
COMMENTS
All terms == 3 (mod 4).
LINKS
Robert Israel, Table of n, a(n) for n = 1..55
EXAMPLE
a(3) = 31 is a term because 31 = 2*3^1+5^2 and 3^1+2*5^2 = 53 are prime.
MAPLE
N:= 10^25: # for terms <= N
R:= NULL:
for a from 1 while 2*3^a < N do
for b from 1 do
x:= 2*3^a+5^b;
if x > N then break fi;
if isprime(x) and isprime(3^a + 2*5^b) then R:= R, x fi
od od:
sort([R]);
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, May 11 2021
STATUS
approved