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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 26 |
| 3 | 272 |
| 4 | 3418 |
| 5 | 44252 |
| 6 | 597104 |
| 7 | 8249152 |
| 8 | 116158298 |
| 9 | 1659335492 |
| 10 | 23979247276 |
| 11 | 349798313152 |
| 12 | 5142733169776 |
| 13 | 76108788764192 |
| 14 | 1132729444052288 |
| 15 | 16940944956246272 |
| 16 | 254449319912898394 |
| 17 | 3836162994088105172 |
| 18 | 58028561918702719604 |
[1,2,26,272,3418,44252,597104,8249152,116158298, 1659335492,23979247276,349798313152,5142733169776, 76108788764192,1132729444052288,16940944956246272, 254449319912898394,3836162994088105172, 58028561918702719604] |