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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 61 |
| 3 | 424 |
| 4 | 4441 |
| 5 | 36844 |
| 6 | 347221 |
| 7 | 3046864 |
| 8 | 27812401 |
| 9 | 248358484 |
| 10 | 2244991981 |
| 11 | 20156099704 |
| 12 | 181649037961 |
| 13 | 1633620638524 |
| 14 | 14708689262341 |
| 15 | 132347685782944 |
| 16 | 1191281759937121 |
| 17 | 10720772899980964 |
| 18 | 96490770797094301 |
| 19 | 868397863687520584 |
| 20 | 7815676140619325881 |
| 21 | 70340608428415729804 |
| 22 | 633067860041532583861 |
| 23 | 5697598819444838176624 |
[1,4,61,424,4441,36844,347221,3046864,27812401, 248358484,2244991981,20156099704,181649037961, 1633620638524,14708689262341,132347685782944, 1191281759937121,10720772899980964, 96490770797094301,868397863687520584, 7815676140619325881,70340608428415729804, 633067860041532583861,5697598819444838176624] |