31.
The rule is Un = (n5 - 17n4 + 111n3 - 349n2 + 518n - 216)/12 for n = 1, 2, 3, ...
The next number in the series 1 2 4 8 10 20 22 is
20
it is 31818 - 8 = 1010 - 4 = 66 - 2 = 44 - 1 = 3
The Pattern is 1^2- 2^2- 3^2- 4^2- 5^2 or 1 - 4 - 9 - 16 - 25 The next number in the series is 6^2 or 36
The next number in the series 2-4-3-9-4 is 16. 2 squared is 4, 3 squared is 9, 4 squared is 16
The next number in the series 1 2 4 8 10 20 22 is
20
it is 31818 - 8 = 1010 - 4 = 66 - 2 = 44 - 1 = 3
4
10
The Pattern is 1^2- 2^2- 3^2- 4^2- 5^2 or 1 - 4 - 9 - 16 - 25 The next number in the series is 6^2 or 36
The next number in the series 2-4-3-9-4 is 16. 2 squared is 4, 3 squared is 9, 4 squared is 16
10
16
The next number is 4. There is a sequence:Add 3, subtract 2, repeat
The next number is 2.
The pattern is - 5 then +2. 2 and 4 are the next numbers in the series.