An awesome number theory question!

Prove that for any integer n>1n>1, n5+n4+1n^5 + n^4 + 1 is not a prime number.

#NumberTheory

Note by Saran Balachandar
4 years, 8 months ago

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Comments

Addingandsubtractingn3n5+n4+n3n3+1=n3(n2+n+1)n3n2n+1=n3(n2+n+1)n(n2+n+1)+(n2+n+1)=(n3n+1)(n2+n+1)TheoriginalexpressionisexpressedasaproductoftwofactorsItisnotaprimenumber.Adding\quad and\quad subtracting\quad { n }^{ 3 }\\ \\ { n }^{ 5 }+{ n }^{ 4 }+n^{ 3 }-{ n }^{ 3 }+1\\ =\quad { n }^{ 3 }({ n }^{ 2 }+n+1)\quad -\quad { n }^{ 3 }-{ n }^{ 2 }-n+1\\ { =\quad n }^{ 3 }({ n }^{ 2 }+n+1)-n({ n }^{ 2 }+n+1)+({ n }^{ 2 }+n+1)\\ =\quad ({ n }^{ 3 }-n+1)({ n }^{ 2 }+n+1)\\ The\quad original\quad expression\quad is\quad expressed\quad as\quad a\quad product\quad of\quad two\quad factors\quad \\ \Longrightarrow \quad It\quad is\quad not\quad a\quad prime\quad number\quad .

Saran Balachandar - 4 years, 8 months ago
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