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PROJECT EULER · #0437

Fibonacci Primitive Roots

Statement only · UnsolvedOriginal problem ↗

When we calculate 8n modulo 11 for n=0 to 9 we get: 1,8,9,6,4,10,3,2,5,7.
As we see all possible values from 1 to 10 occur. So 8 is a primitive root of 11.
But there is more:
If we take a closer look we see:
1+8=9
8+9=176mod11
9+6=154mod11
6+4=10
4+10=143mod11
10+3=132mod11
3+2=5
2+5=7
5+7=121mod11.

So the powers of 8mod11 are cyclic with period 10, and 8n+8n+18n+2(mod11).
8 is called a Fibonacci primitive root of 11.
Not every prime has a Fibonacci primitive root.
There are 323 primes less than 10000 with one or more Fibonacci primitive roots and the sum of these primes is 1480491.
Find the sum of the primes less than 100000000 with at least one Fibonacci primitive root.

Write-up coming later

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