What is the next number in the series: 2, 5, 10, 17, 26,...?

What is the next number in the series: 1, 4, 9, 16, 25,... ?

What is the next number in the series: 17, 33, 50, 83, 133...?

Challenge: What is the sum of the all the numbers in the geometric series

2, 1/4, 1/32, 1/256, .... ?