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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 6 |
| 5 | 16 |
| 6 | 28 |
| 7 | 60 |
| 8 | 142 |
| 9 | 398 |
| 10 | 656 |
| 11 | 1316 |
| 12 | 2654 |
| 13 | 5422 |
| 14 | 11358 |
| 15 | 24714 |
| 16 | 58132 |
| 17 | 163038 |
| 18 | 267946 |
| 19 | 535896 |
| 20 | 1071814 |
| 21 | 2143742 |
| 22 | 4287998 |
| 23 | 8577994 |
| 24 | 17164692 |
| 25 | 34376158 |
| 26 | 68962130 |
| 27 | 138728128 |
| 28 | 280672440 |
| 29 | 574221574 |
| 30 | 1200240586 |
| 31 | 2612191482 |
[1,2,1,6,16,28,60,142,398,656,1316,2654,5422, 11358,24714,58132,163038,267946,535896,1071814, 2143742,4287998,8577994,17164692,34376158, 68962130,138728128,280672440,574221574,1200240586, 2612191482] |