दी गई श्रृंखला में ऐसी कितनी अभाज्य संख्याएँ हैं जिनके ठीक पहले एक सम संख्या और ठीक बाद एक विषम संख्या है? 2 3 1 7 5 9 2 5 4 8 6 7 9 1 6 3 5 4

How many 3s are there in the given sequence that are preceded by an odd number and NOT succeeded by an even number? 1438738553179203553938

In the series given below, how many pairs of successive numbers have a difference of exactly 2 each? 5 6 1 2 4 3 3 5 4 7 1 3 5 6 8 7 6 2 4 8 9