This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 25 |
| 4 | 224 |
| 5 | 2601 |
| 6 | 37072 |
| 7 | 626137 |
| 8 | 12227280 |
| 9 | 271086625 |
| 10 | 6727858496 |
| 11 | 184818121929 |
| 12 | 5568152828416 |
| 13 | 182575550335465 |
| 14 | 6473161538599680 |
| 15 | 246781048203043561 |
| 16 | 10067677495565927168 |
| 17 | 437653901985319521153 |
| 18 | 20197310874805488471040 |
| 19 | 986221173076368356013625 |