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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 34 |
| 6 | 194 |
| 7 | 1208 |
| 8 | 7947 |
| 9 | 54318 |
| 10 | 381918 |
| 11 | 2744560 |
| 12 | 20068358 |
| 13 | 148829716 |
| 14 | 1116773044 |
| 15 | 8463323632 |
| 16 | 64683640051 |
| 17 | 497999144726 |
| 18 | 3858699223862 |
| 19 | 30067745845088 |
| 20 | 235468907374386 |
| 21 | 1852285897565836 |
| 22 | 14629457346782604 |
| 23 | 115964861319175536 |
| 24 | 922269694511198782 |
[0,1,1,2,7,34,194,1208,7947,54318,381918,2744560, 20068358,148829716,1116773044,8463323632, 64683640051,497999144726,3858699223862, 30067745845088,235468907374386,1852285897565836, 14629457346782604,115964861319175536, 922269694511198782] |