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Part of 1969 IMO Shortlist

Problems(1)

Existence of infinitely many a for which n^4+a is composite

Source:

(GDR 2)^{IMO1}

Prove that there exist infinitely many natural numbers

a

with the following property: The number

z = n^4 + a

is not prime for any natural number

n.

number theorySophie Germain identitycomposite numbersIMO ShortlistIMO Longlist