Search API can't search hashtag



I am trying to search #AAPA14 hashtag in my iOS App but I couldn’t get response from the 1.1 API. But it works with #AAPA !

I’ve tried to test search at : but it also returns 0 result.
Also tried with extra parameters like :
count = 50,
result_type = recent

Can any one guide me for the same ? What’s going wrong with #AAPA14, #AAPA13, #AAPA12