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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 13 |
| 6 | 48 |
| 7 | 95 |
| 8 | 424 |
| 9 | 898 |
| 10 | 4837 |
| 11 | 10780 |
| 12 | 68399 |
| 13 | 158111 |
| 14 | 1156224 |
| 15 | 2745145 |
| 16 | 22744380 |
| 17 | 55098660 |
| 18 | 510307001 |
| 19 | 1255610350 |
| 20 | 12859037607 |
| 21 | 32030878113 |
| 22 | 359498491968 |
| 23 | 904385401323 |
| 24 | 11040700820704 |
| 25 | 28000658588542 |
[0,1,2,7,13,48,95,424,898,4837,10780,68399,158111, 1156224,2745145,22744380,55098660,510307001, 1255610350,12859037607,32030878113,359498491968, 904385401323,11040700820704,28000658588542] |