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| n | a(n) |
|---|---|
| 1 | 14 |
| 2 | 76 |
| 3 | 280 |
| 4 | 1240 |
| 5 | 4978 |
| 6 | 21626 |
| 7 | 91058 |
| 8 | 393660 |
| 9 | 1686980 |
| 10 | 7309386 |
| 11 | 31632968 |
| 12 | 137600876 |
| 13 | 599055566 |
| 14 | 2615427970 |
| 15 | 11433493630 |
| 16 | 50075195034 |
| 17 | 219589525108 |
| 18 | 964264276780 |
| 19 | 4238966033150 |
| 20 | 18655002576606 |
| 21 | 82175337524524 |
[14,76,280,1240,4978,21626,91058,393660,1686980, 7309386,31632968,137600876,599055566,2615427970, 11433493630,50075195034,219589525108,964264276780, 4238966033150,18655002576606,82175337524524] |