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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 24 |
| 5 | 70 |
| 6 | 264 |
| 7 | 871 |
| 8 | 3445 |
| 9 | 12209 |
| 10 | 49965 |
| 11 | 186006 |
| 12 | 778897 |
| 13 | 3005994 |
| 14 | 12798041 |
| 15 | 50759402 |
| 16 | 218926582 |
| 17 | 887015121 |
| 18 | 3865566214 |
| 19 | 15933181036 |
| 20 | 70025009803 |
| 21 | 292737848952 |
| 22 | 1295655376440 |
| 23 | 5480826330146 |
| 24 | 24403529986073 |
| 25 | 104271056911262 |
| 26 | 466660480654007 |
| 27 | 2011199904443749 |
| 28 | 9041319778456309 |
[1,1,3,7,24,70,264,871,3445,12209,49965,186006, 778897,3005994,12798041,50759402,218926582, 887015121,3865566214,15933181036,70025009803, 292737848952,1295655376440,5480826330146, 24403529986073,104271056911262,466660480654007, 2011199904443749,9041319778456309] |