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 | 9 |
| 1 | 45 |
| 2 | 285 |
| 3 | 2025 |
| 4 | 15333 |
| 5 | 120825 |
| 6 | 978405 |
| 7 | 8080425 |
| 8 | 67731333 |
| 9 | 574304985 |
| 10 | 4914341925 |
| 11 | 42364319625 |
| 12 | 367428536133 |
| 13 | 3202860761145 |
| 14 | 28037802953445 |
| 15 | 246324856379625 |
| 16 | 2170706132009733 |
| 17 | 19179318935377305 |
| 18 | 169842891165484965 |
| 19 | 1506994510201252425 |