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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 11 |
| 3 | 43 |
| 4 | 180 |
| 5 | 774 |
| 6 | 3431 |
| 7 | 15428 |
| 8 | 70548 |
| 9 | 325431 |
| 10 | 1516925 |
| 11 | 7112596 |
| 12 | 33584632 |
| 13 | 159251552 |
| 14 | 758919860 |
| 15 | 3628089772 |
| 16 | 17408822079 |
| 17 | 83737680086 |
| 18 | 403929643759 |
| 19 | 1952239163441 |
| 20 | 9456497683517 |
| 21 | 45878748056839 |
| 22 | 222983221783390 |
| 23 | 1085170262087486 |
| 24 | 5288848011083883 |
| 25 | 25804657251783199 |
| 26 | 126056290017227100 |
[1,3,11,43,180,774,3431,15428,70548,325431, 1516925,7112596,33584632,159251552,758919860, 3628089772,17408822079,83737680086,403929643759, 1952239163441,9456497683517,45878748056839, 222983221783390,1085170262087486,5288848011083883, 25804657251783199,126056290017227100] |