$9, 27, 31, 155, 161, 1127, ?$

Find the odd number from the given sequence: $1, 5, 14, 30, 50, 91$.

Find the next number in the series: $7, 9, 13, 21, 37, ?$

If $A = \left(\frac{1}{0.4}\right) + \left(\frac{1}{0.04}\right) + \left(\frac{1}{0.004}\right) + \dots$ up to $8$ terms,then what is the value of $A$ (in $.5$)?

Find the missing number in the series: $7, 8, 24, 105, 361, ?$

$4, 30, 160, 810, 4060, \dots$