120 (assuming the pattern is x3, +1, x3, +1...)
It is 43 because 31+12 = 43
If you mean: 1 1 2 3 5 8 13 21 then the next number is 13+21 = 34
The pattern is plus 7. So the next number used to be 1.
1 2 3 4 .12 & .13 & .15 & .18 & .22
89.
eight
What would be the next number in this series 15 12 13 10 11 8?
The next number could be 25. +3, +6, +9, +12 etc.
It is 43 because 31+12 = 43
If you mean: 1 2 3 5 8 13 then the next number is 8+13 = 21
If you mean: 1 1 2 3 5 8 13 21 then the next number is 13+21 = 34
21 and 13. The pattern is t(n) = (-n4 + 10n3 - 23n2 + 38n - 12)/12
The pattern is plus 7. So the next number used to be 1.
prime numbers - next number is 13
1 2 3 4 .12 & .13 & .15 & .18 & .22
37
89.