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 | 1 |
| 3 | 9 |
| 4 | 97 |
| 5 | 1041 |
| 6 | 11169 |
| 7 | 119833 |
| 8 | 1285697 |
| 9 | 13794337 |
| 10 | 148000449 |
| 11 | 1587907625 |
| 12 | 17036776865 |
| 13 | 182788823089 |
| 14 | 1961154631009 |
| 15 | 21041371248697 |
| 16 | 225754408665729 |
| 17 | 2422135536207937 |
| 18 | 25987269043538817 |
| 19 | 278819307278968905 |