40 5 10 20 40 80 160.......double the number each time.
If you mean: 5, 10, 20, 40 then the following number is twice the previous number which will be 80
20
1 to 4
56 (just the next number, not the number that completes the sequence)
80
If you mean: 5 10 20 40 then it is 80
40 5 10 20 40 80 160.......double the number each time.
If you mean: 5, 10, 20, 40 then the following number is twice the previous number which will be 80
Double it every time and so the next number will be 80
A number sequence is not a question. So there can be no "answer".
The next number in the sequence will be 56.
20
20
Divide the sequence by 5 and the answer becomes very obvious: 1, 4, 9, 16,...N2 So, 5, 20, 45, 80,...5N2
The rest of the sequence would be as follows: 40, 20, 10, 5... because each successive number is half of the prior.
{5, 20, 45, 80, 125} = 5{1, 4, 9, 16, 25} = 5{1², 2², 3², 4², 5²} → U{n} = 5n²