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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 92 |
| 5 | 360 |
| 6 | 1515 |
| 7 | 6394 |
| 8 | 27766 |
| 9 | 121701 |
| 10 | 541389 |
| 11 | 2427628 |
| 12 | 10994962 |
| 13 | 50085884 |
| 14 | 229825960 |
| 15 | 1059427008 |
| 16 | 4909468718 |
| 17 | 22840737450 |
| 18 | 106677011512 |
| 19 | 499928196409 |
| 20 | 2349932755977 |
| 21 | 11077508816333 |
| 22 | 52349546603423 |
| 23 | 247976809550402 |
| 24 | 1177163181636024 |
| 25 | 5599152334827215 |
| 26 | 26681459217085335 |
| 27 | 127359498900974016 |
[1,2,7,23,92,360,1515,6394,27766,121701,541389, 2427628,10994962,50085884,229825960,1059427008, 4909468718,22840737450,106677011512,499928196409, 2349932755977,11077508816333,52349546603423, 247976809550402,1177163181636024,5599152334827215, 26681459217085335,127359498900974016] |