- #1

MathematicalPhysicist

Gold Member

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[tex]\sum_{d|n , d<n}[/tex] or [tex]\sum_{d|n}[/tex] both summing over d.

and d|n means d divides n.

I know that I can use Sum[term, {i, n-1}] but I don't know how to use this condition of divisibility to the summation.

any help?

Thanks.