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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 33 |
| 5 | 184 |
| 6 | 1142 |
| 7 | 7629 |
| 8 | 53750 |
| 9 | 394157 |
| 10 | 2981546 |
| 11 | 23117242 |
| 12 | 182867360 |
| 13 | 1470714606 |
| 14 | 11993628444 |
| 15 | 98967634147 |
| 16 | 824958769631 |
| 17 | 6937180941468 |
| 18 | 58785077008641 |
| 19 | 501520244718945 |
| 20 | 4304433733010962 |
| 21 | 37142428443486254 |
| 22 | 322042675618484973 |
| 23 | 2804409601249038670 |
[1,1,2,7,33,184,1142,7629,53750,394157,2981546, 23117242,182867360,1470714606,11993628444, 98967634147,824958769631,6937180941468, 58785077008641,501520244718945,4304433733010962, 37142428443486254,322042675618484973, 2804409601249038670] |