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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 48 |
| 4 | 240 |
| 5 | 1000 |
| 6 | 3300 |
| 7 | 9114 |
| 8 | 21952 |
| 9 | 47520 |
| 10 | 94500 |
| 11 | 175450 |
| 12 | 307824 |
| 13 | 515112 |
| 14 | 828100 |
| 15 | 1286250 |
| 16 | 1939200 |
| 17 | 2848384 |
| 18 | 4088772 |
| 19 | 5750730 |
| 20 | 7942000 |
| 21 | 10789800 |
| 22 | 14443044 |
| 23 | 19074682 |
| 24 | 24884160 |
| 25 | 32100000 |
| 26 | 40982500 |
| 27 | 51826554 |
| 28 | 64964592 |
| 29 | 80769640 |
| 30 | 99658500 |
| 31 | 122095050 |
[1,4,48,240,1000,3300,9114,21952,47520,94500, 175450,307824,515112,828100,1286250,1939200, 2848384,4088772,5750730,7942000,10789800,14443044, 19074682,24884160,32100000,40982500,51826554, 64964592,80769640,99658500,122095050] |