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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 32 |
| 5 | 103 |
| 6 | 361 |
| 7 | 1291 |
| 8 | 4776 |
| 9 | 17539 |
| 10 | 67577 |
| 11 | 255967 |
| 12 | 1001804 |
| 13 | 3907961 |
| 14 | 15484786 |
| 15 | 61440637 |
| 16 | 246958922 |
| 17 | 990680625 |
| 18 | 4026610245 |
| 19 | 16324121493 |
| 20 | 66857579486 |
| 21 | 273568388471 |
| 22 | 1127916470190 |
| 23 | 4647900956921 |
| 24 | 19282067260636 |
| 25 | 79920524162991 |
| 26 | 333276886331913 |
| 27 | 1388649016525857 |
| 28 | 5815906328368270 |
[1,1,4,9,32,103,361,1291,4776,17539,67577,255967, 1001804,3907961,15484786,61440637,246958922, 990680625,4026610245,16324121493,66857579486, 273568388471,1127916470190,4647900956921, 19282067260636,79920524162991,333276886331913, 1388649016525857,5815906328368270] |