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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 132 |
| 2 | 2970 |
| 3 | 19800 |
| 4 | 66462 |
| 5 | 194832 |
| 6 | 420684 |
| 7 | 881760 |
| 8 | 1511730 |
| 9 | 2770284 |
| 10 | 4134240 |
| 11 | 6754968 |
| 12 | 9491130 |
| 13 | 14310120 |
| 14 | 18773964 |
| 15 | 27609648 |
| 16 | 34253142 |
| 17 | 47864520 |
| 18 | 58862870 |
| 19 | 78974808 |
| 20 | 93470652 |
| 21 | 125490024 |
| 22 | 143483340 |
| 23 | 186539760 |
| 24 | 214957644 |
| 25 | 271553700 |
| 26 | 304365600 |
[1,132,2970,19800,66462,194832,420684,881760, 1511730,2770284,4134240,6754968,9491130,14310120, 18773964,27609648,34253142,47864520,58862870, 78974808,93470652,125490024,143483340,186539760, 214957644,271553700,304365600] |