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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 20 |
| 7 | 51 |
| 8 | 184 |
| 9 | 550 |
| 10 | 2009 |
| 11 | 6487 |
| 12 | 23875 |
| 13 | 81724 |
| 14 | 302954 |
| 15 | 1078409 |
| 16 | 4034373 |
| 17 | 14771551 |
| 18 | 55789188 |
| 19 | 208526682 |
| 20 | 794933818 |
| 21 | 3017839193 |
| 22 | 11604938152 |
| 23 | 44590911769 |
| 24 | 172833268057 |
| 25 | 670520982414 |
| 26 | 2617397888002 |
| 27 | 10234831661388 |
| 28 | 40204487779050 |
| 29 | 158254659096516 |
| 30 | 625142808049902 |
[1,1,1,3,6,20,51,184,550,2009,6487,23875,81724, 302954,1078409,4034373,14771551,55789188, 208526682,794933818,3017839193,11604938152, 44590911769,172833268057,670520982414, 2617397888002,10234831661388,40204487779050, 158254659096516,625142808049902] |