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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 31 |
| 4 | 265 |
| 5 | 2446 |
| 6 | 26069 |
| 7 | 294386 |
| 8 | 3628517 |
| 9 | 46938514 |
| 10 | 645978814 |
| 11 | 9265791393 |
| 12 | 139408562319 |
| 13 | 2174338555026 |
| 14 | 35259402634616 |
| 15 | 590187761512336 |
| 16 | 10209739522685893 |
| 17 | 181678453872654154 |
| 18 | 3326776921054665350 |
| 19 | 62485419303819431072 |
| 20 | 1203772979032614462448 |
[1,1,5,31,265,2446,26069,294386,3628517,46938514, 645978814,9265791393,139408562319,2174338555026, 35259402634616,590187761512336,10209739522685893, 181678453872654154,3326776921054665350, 62485419303819431072,1203772979032614462448] |