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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 18 |
| 3 | 99 |
| 4 | 342 |
| 5 | 2691 |
| 6 | 13788 |
| 7 | 65709 |
| 8 | 407772 |
| 9 | 2115981 |
| 10 | 11108358 |
| 11 | 63181719 |
| 12 | 334551402 |
| 13 | 1802963871 |
| 14 | 9931645728 |
| 15 | 53256984129 |
| 16 | 288681869232 |
| 17 | 1572458030361 |
| 18 | 8484410567898 |
| 19 | 46019764248939 |
| 20 | 249748559819262 |
| 21 | 1351163694059451 |
| 22 | 7326501636596868 |
| 23 | 39716608228492149 |
| 24 | 215099382176679492 |
[1,18,99,342,2691,13788,65709,407772,2115981, 11108358,63181719,334551402,1802963871,9931645728, 53256984129,288681869232,1572458030361, 8484410567898,46019764248939,249748559819262, 1351163694059451,7326501636596868, 39716608228492149,215099382176679492] |