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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 49 |
| 5 | 676 |
| 6 | 9409 |
| 7 | 131044 |
| 8 | 1825201 |
| 9 | 25421764 |
| 10 | 354079489 |
| 11 | 4931691076 |
| 12 | 68689595569 |
| 13 | 956722646884 |
| 14 | 13325427460801 |
| 15 | 185599261804324 |
| 16 | 2585064237799729 |
| 17 | 36005300067391876 |
| 18 | 501489136705686529 |
| 19 | 6984842613812219524 |
| 20 | 97286307456665386801 |
[0,1,4,49,676,9409,131044,1825201,25421764, 354079489,4931691076,68689595569,956722646884, 13325427460801,185599261804324,2585064237799729, 36005300067391876,501489136705686529, 6984842613812219524,97286307456665386801] |