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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 69 |
| 6 | 241 |
| 7 | 815 |
| 8 | 2973 |
| 9 | 10765 |
| 10 | 40599 |
| 11 | 153519 |
| 12 | 594441 |
| 13 | 2315819 |
| 14 | 9159005 |
| 15 | 36470431 |
| 16 | 146745519 |
| 17 | 594261517 |
| 18 | 2425275509 |
| 19 | 9954790549 |
| 20 | 41110526691 |
| 21 | 170626390065 |
| 22 | 711716332495 |
| 23 | 2981638200405 |
| 24 | 12543716384153 |
| 25 | 52971343747061 |
| 26 | 224502013317731 |
| 27 | 954637799193723 |
| 28 | 4072108059395579 |
[1,1,3,7,23,69,241,815,2973,10765,40599,153519, 594441,2315819,9159005,36470431,146745519, 594261517,2425275509,9954790549,41110526691, 170626390065,711716332495,2981638200405, 12543716384153,52971343747061,224502013317731, 954637799193723,4072108059395579] |