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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 18 |
| 6 | 98 |
| 7 | 779 |
| 8 | 10589 |
| 9 | 255790 |
| 10 | 11633297 |
| 11 | 1004417286 |
| 12 | 163944008107 |
| 13 | 50324877640599 |
| 14 | 29001521193534445 |
| 15 | 31396727025729968365 |
| 16 | 63969154112074956299242 |
| 17 | 245871360738448777028919520 |
| 18 | 1787330701747389106609369225312 |
| 19 | 24636017249593067184544456944967278 |
[1,1,1,2,5,18,98,779,10589,255790,11633297, 1004417286,163944008107,50324877640599, 29001521193534445,31396727025729968365, 63969154112074956299242, 245871360738448777028919520, 1787330701747389106609369225312, 24636017249593067184544456944967278] |