A097312 Numbers with property that can bring the first digit to the back of the number to get a prime (zeros are dropped).

2, 3, 5, 7, 11, 13, 14, 16, 17, 20, 30, 31, 32, 34, 35, 37, 38, 50, 70, 71, 73, 74, 76, 79, 91, 92, 95, 97, 98, 101, 103, 104, 106, 107, 110, 113, 115, 118, 119, 121, 124, 125, 127, 128, 131, 133, 140, 142, 143, 146, 149, 152, 154, 157, 160, 163, 164, 166, 169, 170

Offset: 1

Author

Jason Earls, Mar 16 2005

Keywords

• base
• easy
• nonn

Comments

First differs from A095179 at a(31) = 103 since A095179(31) = 104 because 401 is prime but 301 = 7 * 43. - Alonso del Arte, Apr 12 2020

Examples

			1234 is in the sequence because 2341 is prime.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..11018 (all terms < 10**5)

Programs

Mathematica

Select[Range[200],PrimeQ[FromDigits[RotateLeft[IntegerDigits[#]]]] &] (* Harvey P. Dale, Jun 06 2018 *)

Python

from sympy import isprime
def ok(n): s = str(n); return isprime(int(s[1:]+s[0]))
print([k for k in range(171) if ok(k)]) # Michael S. Branicky, May 08 2023