Creating indicator for 3 or more consecutive months

[Kwame Archiah]

Hello,

I want to create an indicator variable by id for any individual with 3 or more consecutive months of prescription, using the prescription dates.
I came across the egen seq( )and tried it but it does not exactly do what I want.

Example dataset:
id date
1 09aug2012
1 08nov2012
1 10jan2013
-----------------------------------
2 09may2001
2 23may2001
2 11jul2001
2 01aug2001
2 03oct2001
2 19nov2001
-----------------------------------
3 09nov2004
3 06dec2004
3 01jan2005
3 01mar2005
-----------------------------------

Many thanks for the assistance.

Kwame