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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 34 |
| 4 | 161 |
| 5 | 707 |
| 6 | 3309 |
| 7 | 16892 |
| 8 | 89384 |
| 9 | 465258 |
| 10 | 2414240 |
| 11 | 12658133 |
| 12 | 66882546 |
| 13 | 353898321 |
| 14 | 1874207359 |
| 15 | 9950624881 |
| 16 | 52968141606 |
| 17 | 282452336722 |
| 18 | 1508213363988 |
| 19 | 8064519904852 |
| 20 | 43179574656064 |
| 21 | 231467793567740 |
| 22 | 1242085617391923 |
[4,10,34,161,707,3309,16892,89384,465258,2414240, 12658133,66882546,353898321,1874207359,9950624881, 52968141606,282452336722,1508213363988, 8064519904852,43179574656064,231467793567740, 1242085617391923] |