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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 31 |
| 2 | 465 |
| 3 | 4495 |
| 4 | 31465 |
| 5 | 169911 |
| 6 | 736281 |
| 7 | 2629575 |
| 8 | 7888725 |
| 9 | 20160075 |
| 10 | 44352165 |
| 11 | 84672315 |
| 12 | 141120525 |
| 13 | 206253075 |
| 14 | 265182525 |
| 15 | 300540195 |
| 16 | 300540195 |
| 17 | 265182525 |
| 18 | 206253075 |
| 19 | 141120525 |
| 20 | 84672315 |
| 21 | 44352165 |
| 22 | 20160075 |
| 23 | 7888725 |
| 24 | 2629575 |
| 25 | 736281 |
| 26 | 169911 |
| 27 | 31465 |
| 28 | 4495 |
| 29 | 465 |
[1,31,465,4495,31465,169911,736281,2629575, 7888725,20160075,44352165,84672315,141120525, 206253075,265182525,300540195,300540195,265182525, 206253075,141120525,84672315,44352165,20160075, 7888725,2629575,736281,169911,31465,4495,465] |