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PROJECT EULER · #0572

Idempotent Matrices

Statement only · UnsolvedOriginal problem ↗

A matrix M is called idempotent if M2=M.
Let M be a three by three matrix : M=(abcdefghi).
Let C(n) be the number of idempotent three by three matrices M with integer elements such that
na,b,c,d,e,f,g,h,in.

C(1)=164 and C(2)=848.

Find C(200).

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