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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 48 |
| 5 | 165 |
| 6 | 571 |
| 7 | 1988 |
| 8 | 6953 |
| 9 | 24396 |
| 10 | 85786 |
| 11 | 302104 |
| 12 | 1064945 |
| 13 | 3756519 |
| 14 | 13256712 |
| 15 | 46796545 |
| 16 | 165225380 |
| 17 | 583440086 |
| 18 | 2060408640 |
| 19 | 7276716445 |
| 20 | 25700060995 |
| 21 | 90770326604 |
| 22 | 320598127113 |
| 23 | 1132355884236 |
| 24 | 3999522488002 |
[1,4,14,48,165,571,1988,6953,24396,85786,302104, 1064945,3756519,13256712,46796545,165225380, 583440086,2060408640,7276716445,25700060995, 90770326604,320598127113,1132355884236, 3999522488002] |