| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ackval3 |  |-  ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) | 
						
							| 2 |  | oveq1 |  |-  ( n = 0 -> ( n + 3 ) = ( 0 + 3 ) ) | 
						
							| 3 |  | 3cn |  |-  3 e. CC | 
						
							| 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 e. CC | 
						
							| 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 e. NN0 | 
						
							| 17 | 16 | a1i |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> 0 e. NN0 ) | 
						
							| 18 |  | 5nn0 |  |-  5 e. NN0 | 
						
							| 19 | 18 | a1i |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> 5 e. NN0 ) | 
						
							| 20 | 1 15 17 19 | fvmptd3 |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> ( ( Ack ` 3 ) ` 0 ) = 5 ) | 
						
							| 21 |  | oveq1 |  |-  ( n = 1 -> ( n + 3 ) = ( 1 + 3 ) ) | 
						
							| 22 |  | ax-1cn |  |-  1 e. CC | 
						
							| 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 e. NN0 | 
						
							| 31 |  | 3nn0 |  |-  3 e. NN0 | 
						
							| 32 | 30 31 | deccl |  |-  ; 1 3 e. NN0 | 
						
							| 33 | 32 | nn0cni |  |-  ; 1 3 e. CC | 
						
							| 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 e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> 1 e. NN0 ) | 
						
							| 42 | 32 | a1i |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> ; 1 3 e. NN0 ) | 
						
							| 43 | 1 40 41 42 | fvmptd3 |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> ( ( Ack ` 3 ) ` 1 ) = ; 1 3 ) | 
						
							| 44 |  | oveq1 |  |-  ( n = 2 -> ( n + 3 ) = ( 2 + 3 ) ) | 
						
							| 45 |  | 2cn |  |-  2 e. CC | 
						
							| 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 e. NN0 | 
						
							| 54 |  | 9nn0 |  |-  9 e. NN0 | 
						
							| 55 | 53 54 | deccl |  |-  ; 2 9 e. NN0 | 
						
							| 56 | 55 | nn0cni |  |-  ; 2 9 e. CC | 
						
							| 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 e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> 2 e. NN0 ) | 
						
							| 66 | 55 | a1i |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> ; 2 9 e. NN0 ) | 
						
							| 67 | 1 64 65 66 | fvmptd3 |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 2 ^ ( n + 3 ) ) - 3 ) ) -> ( ( Ack ` 3 ) ` 2 ) = ; 2 9 ) | 
						
							| 68 | 20 43 67 | oteq123d |  |-  ( ( Ack ` 3 ) = ( n e. NN0 |-> ( ( 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 >. |