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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 88 |
| 4 | 1265 |
| 5 | 23916 |
| 6 | 558427 |
| 7 | 15608986 |
| 8 | 508516017 |
| 9 | 18936594712 |
| 10 | 793902926771 |
| 11 | 37017671474334 |
| 12 | 1900666877186761 |
| 13 | 106576903636156084 |
| 14 | 6481047448001720427 |
| 15 | 424870924596413523106 |
| 16 | 29871349825140536394593 |
| 17 | 2242231079099137007066544 |
[1,1,9,88,1265,23916,558427,15608986,508516017, 18936594712,793902926771,37017671474334, 1900666877186761,106576903636156084, 6481047448001720427,424870924596413523106, 29871349825140536394593,2242231079099137007066544] |