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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 25 |
| 4 | 66 |
| 5 | 169 |
| 6 | 425 |
| 7 | 1058 |
| 8 | 2621 |
| 9 | 6485 |
| 10 | 16066 |
| 11 | 39921 |
| 12 | 99601 |
| 13 | 249666 |
| 14 | 628917 |
| 15 | 1592029 |
| 16 | 4048866 |
| 17 | 10341577 |
| 18 | 26517113 |
| 19 | 68226722 |
| 20 | 176065901 |
| 21 | 455514533 |
| 22 | 1181040514 |
| 23 | 3067684065 |
| 24 | 7980068641 |
| 25 | 20784441474 |
| 26 | 54188706405 |
| 27 | 141395801773 |
[1,3,9,25,66,169,425,1058,2621,6485,16066,39921, 99601,249666,628917,1592029,4048866,10341577, 26517113,68226722,176065901,455514533,1181040514, 3067684065,7980068641,20784441474,54188706405, 141395801773] |