Theorem fmtno2prm

Description: The 2 nd Fermat number is a prime (_third Fermat prime_). (Contributed by AV, 13-Jun-2021)

	Ref	Expression
Assertion	fmtno2prm	$$⊢\mathrm{FermatNo}\left(2\right)\in \mathbb{P}$$

Proof

Step	Hyp	Ref	Expression
1		fmtno2	$$⊢\mathrm{FermatNo}\left(2\right)=17$$
2		17prm	$$⊢17\in \mathbb{P}$$
3	1 2	eqeltri	$$⊢\mathrm{FermatNo}\left(2\right)\in \mathbb{P}$$