section 149

A public company can appoint MIn 3 to Max 15 directors, more than 15 requires a special resolution , if no. of director fall below the limit of AOA but still qualify for the limit of companies act 2013, the decision will be valid .as per my knowledge!

Since AOA expressly say to maintain minimum of directors then company shall appoint one or more director to maintain such prescribed limit.

However if such meeting was held and decision was taken for appointment of one more director it will be valid.

Company should also see the minimum number quorum required to hold proper board meeting.

If company don't want to appoint director then first amend the AOA from 4 to 3 as minimum number of directors.

good clarification and information