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A218811 as a simple table
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 61 |
| 4 | 249 |
| 5 | 993 |
| 6 | 3969 |
| 7 | 15871 |
| 8 | 63467 |
| 9 | 253797 |
| 10 | 1014889 |
| 11 | 4058377 |
| 12 | 16228793 |
| 13 | 64896323 |
| 14 | 259509919 |
| 15 | 1037738269 |
| 16 | 4149747805 |
| 17 | 16594171517 |
| 18 | 66357412857 |
| 19 | 265352580967 |
| 20 | 1061102131539 |
| 21 | 4243176114789 |
| 22 | 16967776245057 |
| 23 | 67851397847697 |
[1,15,61,249,993,3969,15871,63467,253797,1014889, 4058377,16228793,64896323,259509919,1037738269, 4149747805,16594171517,66357412857,265352580967, 1061102131539,4243176114789,16967776245057, 67851397847697] |