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 | 196 |
| 5 | 1764 |
| 6 | 17424 |
| 7 | 184041 |
| 8 | 2044900 |
| 9 | 23639044 |
| 10 | 282105616 |
| 11 | 3455793796 |
| 12 | 43268992144 |
| 13 | 551900410000 |
| 14 | 7152629313600 |
| 15 | 93990019574025 |
| 16 | 1250164827828900 |
| 17 | 16807771574144100 |
| 18 | 228138727737690000 |
| 19 | 3123219182728976100 |
| 20 | 43087676888260976400 |
| 21 | 598598221893939680400 |
| 22 | 8369059450146650049600 |