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| n | a(n) |
|---|---|
| 1 | 8 |
| 2 | 20 |
| 3 | 134 |
| 4 | 156 |
| 5 | 2664 |
| 6 | 1224 |
| 7 | 54504 |
| 8 | 9612 |
| 9 | 1119906 |
| 10 | 75492 |
| 11 | 23025384 |
| 12 | 592920 |
| 13 | 473447592 |
| 14 | 4656852 |
| 15 | 9735152022 |
| 16 | 36575388 |
| 17 | 200177107272 |
| 18 | 287266824 |
| 19 | 4116102713928 |
| 20 | 2256222924 |
| 21 | 84636562515282 |
| 22 | 17720604900 |
| 23 | 1740322886860296 |
[8,20,134,156,2664,1224,54504,9612,1119906,75492, 23025384,592920,473447592,4656852,9735152022, 36575388,200177107272,287266824,4116102713928, 2256222924,84636562515282,17720604900, 1740322886860296] |