get employee who absent 5 days sequentially

i want to get employee who absent 5 days sequentially

for example

empno     date   

1             1-1-2015

1             2-1-2015

1             3-1-2015

1             4-1-2015

1             5-1-2015

1            6-1-2015

this employee must appear in the result because he is absent greater than or equal 5 days

empno     date   

1             1-1-2015

1             2-1-2015

3             3-1-2015

2             4-1-2015

4             5-1-2015

1            6-1-2015

but in this example the result is no employees