Project Euler Forum

i don't understand what lowercase g function does, i don't think.
it says g(5)=12 but (1+sqrt(7))^12 expands to something that cannot have a 1 modulo any number.
see wolfram alpha screenshot below:
https://ibb.co/Q9Spv3k

thanks for explaining in advance.

You can verify that (1+sqrt(7))^12=2757056+1041920*sqrt(7) (see also your screenshot of Wolfram)
2757056 mod 5=1 and 1041920 mod 5=0

oh right...my bad.