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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 14 |
| 4 | 122 |
| 5 | 1262 |
| 6 | 15466 |
| 7 | 219646 |
| 8 | 3551194 |
| 9 | 64431374 |
| 10 | 1296712778 |
| 11 | 28672204574 |
| 12 | 691007296954 |
| 13 | 18029138380846 |
| 14 | 506320912190506 |
| 15 | 15228632768870462 |
| 16 | 488405396197019546 |
| 17 | 16638380026019579726 |
| 18 | 600022595692147574794 |
| 19 | 22836184629309211495774 |
| 20 | 914717041435012519583098 |
[1,0,2,14,122,1262,15466,219646,3551194,64431374, 1296712778,28672204574,691007296954, 18029138380846,506320912190506,15228632768870462, 488405396197019546,16638380026019579726, 600022595692147574794,22836184629309211495774, 914717041435012519583098] |