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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 6 |
| 3 | 13 |
| 4 | 27 |
| 5 | 57 |
| 6 | 119 |
| 7 | 250 |
| 8 | 523 |
| 9 | 1097 |
| 10 | 2297 |
| 11 | 4815 |
| 12 | 10086 |
| 13 | 21137 |
| 14 | 44283 |
| 15 | 92793 |
| 16 | 194419 |
| 17 | 407378 |
| 18 | 853559 |
| 19 | 1788481 |
| 20 | 3747361 |
| 21 | 7851867 |
| 22 | 16451910 |
| 23 | 34471669 |
| 24 | 72228171 |
| 25 | 151339401 |
| 26 | 317100335 |
| 27 | 664418698 |
| 28 | 1392152131 |
| 29 | 2916968489 |
| 30 | 6111905849 |
[3,6,13,27,57,119,250,523,1097,2297,4815,10086, 21137,44283,92793,194419,407378,853559,1788481, 3747361,7851867,16451910,34471669,72228171, 151339401,317100335,664418698,1392152131, 2916968489,6111905849] |