Freeflows
Sequence Sum Challenge
A sequence of positive real numbers $ \{a_1, a_2, a_3, \dots\} $ has the property that for $ i \ge 2, $ each $ a_i $ is equal to the sum of all the previous terms. If $ a_{19} = 99, $ then what is $ a_{20} $?
- 1
- 2
- 3
- +
- 4
- 5
- 6
- -
- 7
- 8
- 9
- $\frac{a}{b}$
- .
- 0
- =
- %
- $a^n$
- $a^{\circ}$
- $a_n$
- $\sqrt{}$
- $\sqrt[n]{}$
- $\pi$
- $\ln{}$
- $\log$
- $\theta$
- $\sin{}$
- $\cos{}$
- $\tan{}$
- $($
- $)$
- $[$
- $]$
- $\cap$
- $\cup$
- $,$
- $\infty$