A214587 Greatest common divisor of a number and its last decimal digit: a(n) = gcd(n, n mod 10).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 1, 2, 5, 2, 1, 2, 1, 20, 1, 2, 1, 4, 5, 2, 1, 4, 1, 30, 1, 2, 3, 2, 5, 6, 1, 2, 3, 40, 1, 2, 1, 4, 5, 2, 1, 8, 1, 50, 1, 2, 1, 2, 5, 2, 1, 2, 1, 60, 1, 2, 3, 4, 5, 6, 1, 4, 3, 70, 1, 2, 1, 2, 5, 2, 7, 2, 1, 80, 1, 2, 1, 4, 5

Offset: 0

Author

Alex Ratushnyak, Jul 22 2012

Keywords

• nonn
• base

Examples

			a(69) = gcd(69,9) = 3.
		

Crossrefs

Cf. A068822.

Programs

Java

import java.math.BigInteger;
public class A214587 {
  public static void main (String[] args) {
    for (long n=0; n<222; n++) {
    BigInteger bn=BigInteger.valueOf(n), ld=BigInteger.valueOf(n%10);
    System.out.printf("%s, ", bn.gcd(ld).toString());
    }
  }
}

Mathematica

Table[GCD[n, Mod[n, 10]], {n, 0, 100}] (* T. D. Noe, Jul 24 2012 *)