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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 22 |
| 5 | 66 |
| 6 | 227 |
| 7 | 758 |
| 8 | 2723 |
| 9 | 9807 |
| 10 | 36535 |
| 11 | 136783 |
| 12 | 525245 |
| 13 | 2031029 |
| 14 | 7958899 |
| 15 | 31458447 |
| 16 | 125716531 |
| 17 | 505462106 |
| 18 | 2048274371 |
| 19 | 8355777974 |
| 20 | 34294187162 |
| 21 | 141446086258 |
| 22 | 586560299481 |
| 23 | 2443831656620 |
| 24 | 10223955384759 |
| 25 | 42941361160034 |
| 26 | 181064797061248 |
| 27 | 766076071152554 |
| 28 | 3251480803772371 |
[1,1,3,7,22,66,227,758,2723,9807,36535,136783, 525245,2031029,7958899,31458447,125716531, 505462106,2048274371,8355777974,34294187162, 141446086258,586560299481,2443831656620, 10223955384759,42941361160034,181064797061248, 766076071152554,3251480803772371] |