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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 53 |
| 5 | 233 |
| 6 | 909 |
| 7 | 3361 |
| 8 | 14885 |
| 9 | 61241 |
| 10 | 242717 |
| 11 | 1085329 |
| 12 | 4598229 |
| 13 | 18926889 |
| 14 | 85303757 |
| 15 | 368267009 |
| 16 | 1552593669 |
| 17 | 7041525529 |
| 18 | 30802363261 |
| 19 | 132037599601 |
| 20 | 601853765429 |
| 21 | 2658662122505 |
| 22 | 11537150940205 |
| 23 | 52805458896097 |
| 24 | 235044956158053 |
| 25 | 1029638420961785 |
| 26 | 4728821380317661 |
| 27 | 21177107496077649 |
[1,1,5,17,53,233,909,3361,14885,61241,242717, 1085329,4598229,18926889,85303757,368267009, 1552593669,7041525529,30802363261,132037599601, 601853765429,2658662122505,11537150940205, 52805458896097,235044956158053,1029638420961785, 4728821380317661,21177107496077649] |