Dubs checking algos.

Post your dubs-checking algorithms. We have a lot spread out but it might be nice to collect all the good ones in a single thread. Revised version of an earlier one I wrote:

Number isDubs := method(
if(self toBase(11) asNumber mod(10) == 0,
Exception raise("checkem"); true,
false))

``#include <stdio.h>

void main()
{
int i;
for(i =0;i<100;i++)
{
if(i%11)
{
printf("Singles\n");
}
else
{
printf("%d, Check 'em\n",i);
}
}
}``

i can never figure out code tags