OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3)=13 is a member because 13 and 131413 are primes.
MAPLE
f:= proc(n) local d; d:=10^(ilog10(n)+1);
n*(d^2+d+1)+d
end proc:
select(t -> isprime(t) and isprime(f(t)), [seq(i, i=3..10000, 2)]);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, Dec 26 2019
STATUS
approved