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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 724 |
| 3 | 34091 |
| 4 | 524288 |
| 5 | 4367320 |
| 6 | 24685212 |
| 7 | 106765608 |
| 8 | 379625062 |
| 9 | 1162261467 |
| 10 | 3162277660 |
| 11 | 7820427766 |
| 12 | 17874003451 |
| 13 | 38235066239 |
| 14 | 77306558317 |
| 15 | 148890490631 |
| 16 | 274877906944 |
| 17 | 488950340714 |
| 18 | 841567195983 |
| 19 | 1406563064942 |
| 20 | 2289733608959 |
| 21 | 3639848436450 |
| 22 | 5662594565481 |
[0,1,724,34091,524288,4367320,24685212,106765608, 379625062,1162261467,3162277660,7820427766, 17874003451,38235066239,77306558317,148890490631, 274877906944,488950340714,841567195983, 1406563064942,2289733608959,3639848436450, 5662594565481] |