| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nnnn0 | ⊢ ( 𝑁  ∈  ℕ  →  𝑁  ∈  ℕ0 ) | 
						
							| 2 |  | faccl | ⊢ ( 𝑁  ∈  ℕ0  →  ( ! ‘ 𝑁 )  ∈  ℕ ) | 
						
							| 3 |  | elnnuz | ⊢ ( ( ! ‘ 𝑁 )  ∈  ℕ  ↔  ( ! ‘ 𝑁 )  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 4 |  | eluzp1p1 | ⊢ ( ( ! ‘ 𝑁 )  ∈  ( ℤ≥ ‘ 1 )  →  ( ( ! ‘ 𝑁 )  +  1 )  ∈  ( ℤ≥ ‘ ( 1  +  1 ) ) ) | 
						
							| 5 |  | df-2 | ⊢ 2  =  ( 1  +  1 ) | 
						
							| 6 | 5 | fveq2i | ⊢ ( ℤ≥ ‘ 2 )  =  ( ℤ≥ ‘ ( 1  +  1 ) ) | 
						
							| 7 | 4 6 | eleqtrrdi | ⊢ ( ( ! ‘ 𝑁 )  ∈  ( ℤ≥ ‘ 1 )  →  ( ( ! ‘ 𝑁 )  +  1 )  ∈  ( ℤ≥ ‘ 2 ) ) | 
						
							| 8 | 3 7 | sylbi | ⊢ ( ( ! ‘ 𝑁 )  ∈  ℕ  →  ( ( ! ‘ 𝑁 )  +  1 )  ∈  ( ℤ≥ ‘ 2 ) ) | 
						
							| 9 |  | exprmfct | ⊢ ( ( ( ! ‘ 𝑁 )  +  1 )  ∈  ( ℤ≥ ‘ 2 )  →  ∃ 𝑝  ∈  ℙ 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) | 
						
							| 10 | 2 8 9 | 3syl | ⊢ ( 𝑁  ∈  ℕ0  →  ∃ 𝑝  ∈  ℙ 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) | 
						
							| 11 |  | prmz | ⊢ ( 𝑝  ∈  ℙ  →  𝑝  ∈  ℤ ) | 
						
							| 12 |  | nn0z | ⊢ ( 𝑁  ∈  ℕ0  →  𝑁  ∈  ℤ ) | 
						
							| 13 |  | eluz | ⊢ ( ( 𝑝  ∈  ℤ  ∧  𝑁  ∈  ℤ )  →  ( 𝑁  ∈  ( ℤ≥ ‘ 𝑝 )  ↔  𝑝  ≤  𝑁 ) ) | 
						
							| 14 | 11 12 13 | syl2an | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ℕ0 )  →  ( 𝑁  ∈  ( ℤ≥ ‘ 𝑝 )  ↔  𝑝  ≤  𝑁 ) ) | 
						
							| 15 |  | prmuz2 | ⊢ ( 𝑝  ∈  ℙ  →  𝑝  ∈  ( ℤ≥ ‘ 2 ) ) | 
						
							| 16 |  | eluz2b2 | ⊢ ( 𝑝  ∈  ( ℤ≥ ‘ 2 )  ↔  ( 𝑝  ∈  ℕ  ∧  1  <  𝑝 ) ) | 
						
							| 17 | 15 16 | sylib | ⊢ ( 𝑝  ∈  ℙ  →  ( 𝑝  ∈  ℕ  ∧  1  <  𝑝 ) ) | 
						
							| 18 | 17 | adantr | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  ( 𝑝  ∈  ℕ  ∧  1  <  𝑝 ) ) | 
						
							| 19 | 18 | simpld | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑝  ∈  ℕ ) | 
						
							| 20 | 19 | nnnn0d | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑝  ∈  ℕ0 ) | 
						
							| 21 |  | eluznn0 | ⊢ ( ( 𝑝  ∈  ℕ0  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑁  ∈  ℕ0 ) | 
						
							| 22 | 20 21 | sylancom | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑁  ∈  ℕ0 ) | 
						
							| 23 |  | nnz | ⊢ ( ( ! ‘ 𝑁 )  ∈  ℕ  →  ( ! ‘ 𝑁 )  ∈  ℤ ) | 
						
							| 24 | 22 2 23 | 3syl | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  ( ! ‘ 𝑁 )  ∈  ℤ ) | 
						
							| 25 | 18 | simprd | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  1  <  𝑝 ) | 
						
							| 26 |  | dvdsfac | ⊢ ( ( 𝑝  ∈  ℕ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑝  ∥  ( ! ‘ 𝑁 ) ) | 
						
							| 27 | 19 26 | sylancom | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  𝑝  ∥  ( ! ‘ 𝑁 ) ) | 
						
							| 28 |  | ndvdsp1 | ⊢ ( ( ( ! ‘ 𝑁 )  ∈  ℤ  ∧  𝑝  ∈  ℕ  ∧  1  <  𝑝 )  →  ( 𝑝  ∥  ( ! ‘ 𝑁 )  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) ) | 
						
							| 29 | 28 | imp | ⊢ ( ( ( ( ! ‘ 𝑁 )  ∈  ℤ  ∧  𝑝  ∈  ℕ  ∧  1  <  𝑝 )  ∧  𝑝  ∥  ( ! ‘ 𝑁 ) )  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) | 
						
							| 30 | 24 19 25 27 29 | syl31anc | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ( ℤ≥ ‘ 𝑝 ) )  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) | 
						
							| 31 | 30 | ex | ⊢ ( 𝑝  ∈  ℙ  →  ( 𝑁  ∈  ( ℤ≥ ‘ 𝑝 )  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) ) | 
						
							| 32 | 31 | adantr | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ℕ0 )  →  ( 𝑁  ∈  ( ℤ≥ ‘ 𝑝 )  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) ) | 
						
							| 33 | 14 32 | sylbird | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ℕ0 )  →  ( 𝑝  ≤  𝑁  →  ¬  𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 ) ) ) | 
						
							| 34 | 33 | con2d | ⊢ ( ( 𝑝  ∈  ℙ  ∧  𝑁  ∈  ℕ0 )  →  ( 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 )  →  ¬  𝑝  ≤  𝑁 ) ) | 
						
							| 35 | 34 | ancoms | ⊢ ( ( 𝑁  ∈  ℕ0  ∧  𝑝  ∈  ℙ )  →  ( 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 )  →  ¬  𝑝  ≤  𝑁 ) ) | 
						
							| 36 |  | nn0re | ⊢ ( 𝑁  ∈  ℕ0  →  𝑁  ∈  ℝ ) | 
						
							| 37 | 11 | zred | ⊢ ( 𝑝  ∈  ℙ  →  𝑝  ∈  ℝ ) | 
						
							| 38 |  | ltnle | ⊢ ( ( 𝑁  ∈  ℝ  ∧  𝑝  ∈  ℝ )  →  ( 𝑁  <  𝑝  ↔  ¬  𝑝  ≤  𝑁 ) ) | 
						
							| 39 | 36 37 38 | syl2an | ⊢ ( ( 𝑁  ∈  ℕ0  ∧  𝑝  ∈  ℙ )  →  ( 𝑁  <  𝑝  ↔  ¬  𝑝  ≤  𝑁 ) ) | 
						
							| 40 | 35 39 | sylibrd | ⊢ ( ( 𝑁  ∈  ℕ0  ∧  𝑝  ∈  ℙ )  →  ( 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 )  →  𝑁  <  𝑝 ) ) | 
						
							| 41 | 40 | reximdva | ⊢ ( 𝑁  ∈  ℕ0  →  ( ∃ 𝑝  ∈  ℙ 𝑝  ∥  ( ( ! ‘ 𝑁 )  +  1 )  →  ∃ 𝑝  ∈  ℙ 𝑁  <  𝑝 ) ) | 
						
							| 42 | 10 41 | mpd | ⊢ ( 𝑁  ∈  ℕ0  →  ∃ 𝑝  ∈  ℙ 𝑁  <  𝑝 ) | 
						
							| 43 | 1 42 | syl | ⊢ ( 𝑁  ∈  ℕ  →  ∃ 𝑝  ∈  ℙ 𝑁  <  𝑝 ) |