OFFSET
1,1
COMMENTS
Primes that remain prime upon deleting the first and last digits.
LINKS
Jason Yuen, Table of n, a(n) for n = 1..10000 (correcting Christian N. K. Anderson previous bfile).
MATHEMATICA
Select[Range[100, 853], PrimeQ[#] && PrimeQ[FromDigits[Rest[Most[IntegerDigits[#]]]]] &] (* T. D. Noe, Apr 05 2013 *)
PROG
(PARI) {indigs(n)=local(j, a, d); n=n\10; j=1; a=0; while(n>10, d=divrem(n, 10); n=d[1]; a=a+j*d[2]; j=10*j); a}
forprime(p=1, 855, if(isprime(indigs(p)), print1(p, ", "))) \\ Klaus Brockhaus, Nov 06 2002
(Python)
from sympy import isprime
for p in filter(isprime, range(100, 855)):
if isprime(int(str(p)[1:-1])): print(p) # Jason Yuen, Mar 28 2024
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Amarnath Murthy, Nov 05 2002
EXTENSIONS
Edited and extended by Klaus Brockhaus, Nov 06 2002
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 21 2007
STATUS
approved