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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 26 |
| 4 | 117 |
| 5 | 485 |
| 6 | 2072 |
| 7 | 8749 |
| 8 | 37107 |
| 9 | 157114 |
| 10 | 665665 |
| 11 | 2819609 |
| 12 | 11944368 |
| 13 | 50596649 |
| 14 | 214331663 |
| 15 | 907922170 |
| 16 | 3846022173 |
| 17 | 16292007901 |
| 18 | 69014058568 |
| 19 | 292348234421 |
| 20 | 1238407008795 |
| 21 | 5245976249306 |
| 22 | 22222312038857 |
| 23 | 94135224351601 |
| 24 | 398763209531232 |
| 25 | 1689188062337425 |
[0,1,7,26,117,485,2072,8749,37107,157114,665665, 2819609,11944368,50596649,214331663,907922170, 3846022173,16292007901,69014058568,292348234421, 1238407008795,5245976249306,22222312038857, 94135224351601,398763209531232,1689188062337425] |