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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 18 |
| 6 | 40 |
| 7 | 91 |
| 8 | 210 |
| 9 | 492 |
| 10 | 1165 |
| 11 | 2786 |
| 12 | 6710 |
| 13 | 16267 |
| 14 | 39650 |
| 15 | 97108 |
| 16 | 238824 |
| 17 | 589521 |
| 18 | 1459960 |
| 19 | 3626213 |
| 20 | 9030450 |
| 21 | 22542396 |
| 22 | 56393792 |
| 23 | 141358274 |
| 24 | 354975429 |
| 25 | 892893120 |
| 26 | 2249412290 |
| 27 | 5674891000 |
| 28 | 14335757256 |
| 29 | 36259245522 |
| 30 | 91815545800 |
[1,2,4,8,18,40,91,210,492,1165,2786,6710,16267, 39650,97108,238824,589521,1459960,3626213,9030450, 22542396,56393792,141358274,354975429,892893120, 2249412290,5674891000,14335757256,36259245522, 91815545800] |