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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 93 |
| 6 | 359 |
| 7 | 1332 |
| 8 | 5400 |
| 9 | 21460 |
| 10 | 89844 |
| 11 | 373197 |
| 12 | 1600682 |
| 13 | 6853799 |
| 14 | 29959582 |
| 15 | 131136020 |
| 16 | 582046108 |
| 17 | 2590492619 |
| 18 | 11642984469 |
| 19 | 52500378935 |
| 20 | 238444506195 |
| 21 | 1086573825315 |
| 22 | 4978762863254 |
| 23 | 22885862700737 |
| 24 | 105659026464329 |
| 25 | 489244652473495 |
| 26 | 2273483149291092 |
| 27 | 10593076963481771 |
| 28 | 49504781707787203 |
[1,1,3,8,28,93,359,1332,5400,21460,89844,373197, 1600682,6853799,29959582,131136020,582046108, 2590492619,11642984469,52500378935,238444506195, 1086573825315,4978762863254,22885862700737, 105659026464329,489244652473495,2273483149291092, 10593076963481771,49504781707787203] |