| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ackval3 | ⊢ ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) ) | 
						
							| 2 |  | oveq1 | ⊢ ( 𝑛  =  0  →  ( 𝑛  +  3 )  =  ( 0  +  3 ) ) | 
						
							| 3 |  | 3cn | ⊢ 3  ∈  ℂ | 
						
							| 4 | 3 | addlidi | ⊢ ( 0  +  3 )  =  3 | 
						
							| 5 | 2 4 | eqtrdi | ⊢ ( 𝑛  =  0  →  ( 𝑛  +  3 )  =  3 ) | 
						
							| 6 | 5 | oveq2d | ⊢ ( 𝑛  =  0  →  ( 2 ↑ ( 𝑛  +  3 ) )  =  ( 2 ↑ 3 ) ) | 
						
							| 7 | 6 | oveq1d | ⊢ ( 𝑛  =  0  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  ( ( 2 ↑ 3 )  −  3 ) ) | 
						
							| 8 |  | cu2 | ⊢ ( 2 ↑ 3 )  =  8 | 
						
							| 9 | 8 | oveq1i | ⊢ ( ( 2 ↑ 3 )  −  3 )  =  ( 8  −  3 ) | 
						
							| 10 |  | 5cn | ⊢ 5  ∈  ℂ | 
						
							| 11 |  | 5p3e8 | ⊢ ( 5  +  3 )  =  8 | 
						
							| 12 | 11 | eqcomi | ⊢ 8  =  ( 5  +  3 ) | 
						
							| 13 | 10 3 12 | mvrraddi | ⊢ ( 8  −  3 )  =  5 | 
						
							| 14 | 9 13 | eqtri | ⊢ ( ( 2 ↑ 3 )  −  3 )  =  5 | 
						
							| 15 | 7 14 | eqtrdi | ⊢ ( 𝑛  =  0  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  5 ) | 
						
							| 16 |  | 0nn0 | ⊢ 0  ∈  ℕ0 | 
						
							| 17 | 16 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  0  ∈  ℕ0 ) | 
						
							| 18 |  | 5nn0 | ⊢ 5  ∈  ℕ0 | 
						
							| 19 | 18 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  5  ∈  ℕ0 ) | 
						
							| 20 | 1 15 17 19 | fvmptd3 | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  ( ( Ack ‘ 3 ) ‘ 0 )  =  5 ) | 
						
							| 21 |  | oveq1 | ⊢ ( 𝑛  =  1  →  ( 𝑛  +  3 )  =  ( 1  +  3 ) ) | 
						
							| 22 |  | ax-1cn | ⊢ 1  ∈  ℂ | 
						
							| 23 |  | 3p1e4 | ⊢ ( 3  +  1 )  =  4 | 
						
							| 24 | 3 22 23 | addcomli | ⊢ ( 1  +  3 )  =  4 | 
						
							| 25 | 21 24 | eqtrdi | ⊢ ( 𝑛  =  1  →  ( 𝑛  +  3 )  =  4 ) | 
						
							| 26 | 25 | oveq2d | ⊢ ( 𝑛  =  1  →  ( 2 ↑ ( 𝑛  +  3 ) )  =  ( 2 ↑ 4 ) ) | 
						
							| 27 | 26 | oveq1d | ⊢ ( 𝑛  =  1  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  ( ( 2 ↑ 4 )  −  3 ) ) | 
						
							| 28 |  | 2exp4 | ⊢ ( 2 ↑ 4 )  =  ; 1 6 | 
						
							| 29 | 28 | oveq1i | ⊢ ( ( 2 ↑ 4 )  −  3 )  =  ( ; 1 6  −  3 ) | 
						
							| 30 |  | 1nn0 | ⊢ 1  ∈  ℕ0 | 
						
							| 31 |  | 3nn0 | ⊢ 3  ∈  ℕ0 | 
						
							| 32 | 30 31 | deccl | ⊢ ; 1 3  ∈  ℕ0 | 
						
							| 33 | 32 | nn0cni | ⊢ ; 1 3  ∈  ℂ | 
						
							| 34 |  | eqid | ⊢ ; 1 3  =  ; 1 3 | 
						
							| 35 |  | 3p3e6 | ⊢ ( 3  +  3 )  =  6 | 
						
							| 36 | 30 31 31 34 35 | decaddi | ⊢ ( ; 1 3  +  3 )  =  ; 1 6 | 
						
							| 37 | 36 | eqcomi | ⊢ ; 1 6  =  ( ; 1 3  +  3 ) | 
						
							| 38 | 33 3 37 | mvrraddi | ⊢ ( ; 1 6  −  3 )  =  ; 1 3 | 
						
							| 39 | 29 38 | eqtri | ⊢ ( ( 2 ↑ 4 )  −  3 )  =  ; 1 3 | 
						
							| 40 | 27 39 | eqtrdi | ⊢ ( 𝑛  =  1  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  ; 1 3 ) | 
						
							| 41 | 30 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  1  ∈  ℕ0 ) | 
						
							| 42 | 32 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  ; 1 3  ∈  ℕ0 ) | 
						
							| 43 | 1 40 41 42 | fvmptd3 | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  ( ( Ack ‘ 3 ) ‘ 1 )  =  ; 1 3 ) | 
						
							| 44 |  | oveq1 | ⊢ ( 𝑛  =  2  →  ( 𝑛  +  3 )  =  ( 2  +  3 ) ) | 
						
							| 45 |  | 2cn | ⊢ 2  ∈  ℂ | 
						
							| 46 |  | 3p2e5 | ⊢ ( 3  +  2 )  =  5 | 
						
							| 47 | 3 45 46 | addcomli | ⊢ ( 2  +  3 )  =  5 | 
						
							| 48 | 44 47 | eqtrdi | ⊢ ( 𝑛  =  2  →  ( 𝑛  +  3 )  =  5 ) | 
						
							| 49 | 48 | oveq2d | ⊢ ( 𝑛  =  2  →  ( 2 ↑ ( 𝑛  +  3 ) )  =  ( 2 ↑ 5 ) ) | 
						
							| 50 | 49 | oveq1d | ⊢ ( 𝑛  =  2  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  ( ( 2 ↑ 5 )  −  3 ) ) | 
						
							| 51 |  | 2exp5 | ⊢ ( 2 ↑ 5 )  =  ; 3 2 | 
						
							| 52 | 51 | oveq1i | ⊢ ( ( 2 ↑ 5 )  −  3 )  =  ( ; 3 2  −  3 ) | 
						
							| 53 |  | 2nn0 | ⊢ 2  ∈  ℕ0 | 
						
							| 54 |  | 9nn0 | ⊢ 9  ∈  ℕ0 | 
						
							| 55 | 53 54 | deccl | ⊢ ; 2 9  ∈  ℕ0 | 
						
							| 56 | 55 | nn0cni | ⊢ ; 2 9  ∈  ℂ | 
						
							| 57 |  | eqid | ⊢ ; 2 9  =  ; 2 9 | 
						
							| 58 |  | 2p1e3 | ⊢ ( 2  +  1 )  =  3 | 
						
							| 59 |  | 9p3e12 | ⊢ ( 9  +  3 )  =  ; 1 2 | 
						
							| 60 | 53 54 31 57 58 53 59 | decaddci | ⊢ ( ; 2 9  +  3 )  =  ; 3 2 | 
						
							| 61 | 60 | eqcomi | ⊢ ; 3 2  =  ( ; 2 9  +  3 ) | 
						
							| 62 | 56 3 61 | mvrraddi | ⊢ ( ; 3 2  −  3 )  =  ; 2 9 | 
						
							| 63 | 52 62 | eqtri | ⊢ ( ( 2 ↑ 5 )  −  3 )  =  ; 2 9 | 
						
							| 64 | 50 63 | eqtrdi | ⊢ ( 𝑛  =  2  →  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 )  =  ; 2 9 ) | 
						
							| 65 | 53 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  2  ∈  ℕ0 ) | 
						
							| 66 | 55 | a1i | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  ; 2 9  ∈  ℕ0 ) | 
						
							| 67 | 1 64 65 66 | fvmptd3 | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  ( ( Ack ‘ 3 ) ‘ 2 )  =  ; 2 9 ) | 
						
							| 68 | 20 43 67 | oteq123d | ⊢ ( ( Ack ‘ 3 )  =  ( 𝑛  ∈  ℕ0  ↦  ( ( 2 ↑ ( 𝑛  +  3 ) )  −  3 ) )  →  〈 ( ( Ack ‘ 3 ) ‘ 0 ) ,  ( ( Ack ‘ 3 ) ‘ 1 ) ,  ( ( Ack ‘ 3 ) ‘ 2 ) 〉  =  〈 5 ,  ; 1 3 ,  ; 2 9 〉 ) | 
						
							| 69 | 1 68 | ax-mp | ⊢ 〈 ( ( Ack ‘ 3 ) ‘ 0 ) ,  ( ( Ack ‘ 3 ) ‘ 1 ) ,  ( ( Ack ‘ 3 ) ‘ 2 ) 〉  =  〈 5 ,  ; 1 3 ,  ; 2 9 〉 |