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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 15 |
| 4 | 39 |
| 5 | 97 |
| 6 | 244 |
| 7 | 610 |
| 8 | 1525 |
| 9 | 3814 |
| 10 | 9536 |
| 11 | 23841 |
| 12 | 59604 |
| 13 | 149011 |
| 14 | 372529 |
| 15 | 931322 |
| 16 | 2328306 |
| 17 | 5820766 |
| 18 | 14551915 |
| 19 | 36379788 |
| 20 | 90949470 |
| 21 | 227373675 |
| 22 | 568434188 |
| 23 | 1421085471 |
| 24 | 3552713678 |
| 25 | 8881784197 |
| 26 | 22204460492 |
| 27 | 55511151231 |
| 28 | 138777878078 |
| 29 | 346944695195 |
| 30 | 867361737988 |
[1,2,6,15,39,97,244,610,1525,3814,9536,23841, 59604,149011,372529,931322,2328306,5820766, 14551915,36379788,90949470,227373675,568434188, 1421085471,3552713678,8881784197,22204460492, 55511151231,138777878078,346944695195, 867361737988] |