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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 59 |
| 5 | 237 |
| 6 | 1117 |
| 7 | 4876 |
| 8 | 23484 |
| 9 | 107063 |
| 10 | 521987 |
| 11 | 2442075 |
| 12 | 11995134 |
| 13 | 57056591 |
| 14 | 281598695 |
| 15 | 1354666528 |
| 16 | 6707399025 |
| 17 | 32526399379 |
| 18 | 161411737737 |
| 19 | 787355791682 |
| 20 | 3913582816735 |
| 21 | 19175058749533 |
| 22 | 95424679112641 |
| 23 | 469146070330091 |
| 24 | 2336818911143639 |
| 25 | 11519647002903261 |
| 26 | 57419336864686471 |
| 27 | 283663564494396519 |
[1,1,4,13,59,237,1117,4876,23484,107063,521987, 2442075,11995134,57056591,281598695,1354666528, 6707399025,32526399379,161411737737,787355791682, 3913582816735,19175058749533,95424679112641, 469146070330091,2336818911143639, 11519647002903261,57419336864686471, 283663564494396519] |