Which type of power plant generates electricity by

What should come in place of (?) question mark in the given number series.

81, 73, 66, 60, 55, ?

14 6 4 4 ? 48

What should come in place of (?) question mark in the following number series.

5, 11, 23, 47, 95, ?

In each of the following number series, one term is missing. Find the missing term.

1, 4, 9, 16, 25, ?

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

4, 11, 32, 95, 284, 851, ?

156, 182, 210, 240, 272, ?

31      32        35       ?        47         56

What should come in place of (?) question mark in the following number series.

1, 2, 6, 24, 120, ?

What value should come in the place of (?) in the following number series?

71, 72, 76, 103, ?, 244

254, ?, 1022, 1150, 1214, 1246