OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
127 becomes 271 which is also a prime.
MAPLE
R:= 2, 3, 5, 7:
for d from 1 to 3 do
for i in [1, 3, 7, 9] do
for x from 1 to 10^d-1 by 2 do
y:= i*10^d+x;
if isprime(y) and isprime(10*x+i) then R:= R, y fi
od od od:
R; # Robert Israel, Aug 05 2020
MATHEMATICA
Select[Prime[Range[200]], PrimeQ[FromDigits[RotateLeft[IntegerDigits[#]]]]&] (* Paolo Xausa, Nov 13 2023 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, May 04 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), May 25 2001
STATUS
approved