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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 14 |
| 3 | 52 |
| 4 | 198 |
| 5 | 764 |
| 6 | 2976 |
| 7 | 11668 |
| 8 | 45960 |
| 9 | 181652 |
| 10 | 719784 |
| 11 | 2788796 |
| 12 | 11002420 |
| 13 | 43580832 |
| 14 | 173051000 |
| 15 | 688262544 |
| 16 | 2700639584 |
| 17 | 10713025424 |
| 18 | 42598244032 |
| 19 | 167252123936 |
| 20 | 663795796428 |
| 21 | 2640605536256 |
| 22 | 10519121286540 |
| 23 | 41513829916044 |
[4,14,52,198,764,2976,11668,45960,181652,719784, 2788796,11002420,43580832,173051000,688262544, 2700639584,10713025424,42598244032,167252123936, 663795796428,2640605536256,10519121286540, 41513829916044] |