18
The sequence is of two alternating series of numbers.
The first series starts with 3 and increments by 3
i.e. 3,-,6,-,9,-,
The second series starts with 4 and increments by 4
i.e. -,4,-,8,-,12,-,16
But when the '3' series reaches a number which has already been used by the '4' series, it adds another 3,
i.e. 3,4,6,8,9,12,15,16,18,
Following this pattern, the series would continue
3,4,6,8,9,12,15,16,18,20,21,24,27,28,30,32,33,36,39etc
10
57
One number does not make a sequence (nor a series).
The number 7 comes next.
mcmlx
10
57
One number does not make a sequence (nor a series).
11 comes next.
The number 7 comes next.
There is no series of number: just one very large number!
10
mcmlx
It is: 4554
A single number cannot define a sequence, even less a series.
The next number is the sequence 236175969, 48, 12 is 236175861.
the answer is three