The correct sequence of events in India is 1, 2, 3.

1. Mahalanobis Model: This model, also known as the Second Five-Year Plan, was implemented in India from 1956 to 1961. It aimed to promote heavy industry and reduce dependence on imports.

2. Plan Holiday: India faced a severe economic crisis in the early 1960s, leading to what is known as the "Plan Holiday". During this period, there was a pause in the formulation and implementation of new Five-Year Plans.

3. Rolling Plan: After the Plan Holiday, the concept of the Rolling Plan was introduced in India. This was a flexible planning framework where plans were formulated for shorter durations, typically three years. It allowed for continuous adjustment and modifications in the planning process.

Therefore, the correct sequence is 1 (Mahalanobis Model), 2 (Plan Holiday), and 3 (Rolling Plan).