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Problem #70

Fibonacci Circle

circles

All circles in the picture above are tangent to each other. If radius R1=2^{12}, R2=2^{11} and R3=2^{10}, calculate r, radius of the inner yellow circle. Let x=\lfloor{r}\rfloor \times 10^{14}.

We now define a new sequence as

F(n) = F(n-1) + F(n-2) + (n-1) \forall n \geq 2

with F(0) = 0 & F(1) =1.

Calculate sum \{F(0) + F(1) + F(2) + ... + F(x-1) + F(x)\} \bmod {1000000007}.

Contributed by Adarsh Kumar

Solved by 36 users

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