It was a special reunion between them and  their 

12      18      31     51     ?     112

What will come in place of the question mark (?) in the following series?

81, 83, 87, 95, 111, ?

What will come in place of the question mark (?) in the following series?

20, 21, 30, 55, 104, 185, ?

0, 6, 24, ?, 120, 210

92, 88, 79, ?,  38, 2

12, 19, 33, ?, 117

18, 30, 50, 102, 282, ?

What will come in place of the question mark (?) in the following series?

32, ?, 30, 46, 28, 44

Find the missing number in the given number series.

?, 26, 38, 70, 130, 226

17, 38, 123, 508, ?, 15426