Question 943261
OK so the first number choice you have 60 choices. 
The second number, you start with 60 choices but then subtract 3 for the previous number and its neighbors. So the second choice leaves you with 57 choices. 
The third choice you start with 60 choices but then subtract 3 for the previous number and its neighbors. 
So,
{{{N=60*57*57=194940}}}