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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 92 |
| 6 | 424 |
| 7 | 2100 |
| 8 | 10952 |
| 9 | 59220 |
| 10 | 328454 |
| 11 | 1855548 |
| 12 | 10630282 |
| 13 | 61585456 |
| 14 | 360139296 |
| 15 | 2123022032 |
| 16 | 12603671392 |
| 17 | 75291625002 |
| 18 | 452279294266 |
| 19 | 2730374221784 |
| 20 | 16556643025496 |
| 21 | 100801159909630 |
| 22 | 615936184506514 |
[1,2,6,22,92,424,2100,10952,59220,328454,1855548, 10630282,61585456,360139296,2123022032, 12603671392,75291625002,452279294266, 2730374221784,16556643025496,100801159909630, 615936184506514] |