Which is the next in the series?

3,13,31,57, ……

If A=B/2; B=C²/2; c=2√3. Which is A of the following?

If A means +, B means -, C means x and D means /, then the value of 18C14A6B16D4 is:

find out the missing term:

99, 98, 94, 85, 69, 44,...

find out the missing term:

7, 13,21, ....,43,57

IF CA=31, GE=75, FH=