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 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 57 |
| 4 | 658 |
| 5 | 8442 |
| 6 | 115692 |
| 7 | 1658505 |
| 8 | 24565530 |
| 9 | 372999198 |
| 10 | 5774883348 |
| 11 | 90821581578 |
| 12 | 1446901409268 |
| 13 | 23301338376916 |
| 14 | 378711707274072 |
| 15 | 6203898306232233 |
| 16 | 102329366764727658 |
| 17 | 1698047225583890550 |
| 18 | 28327664136201303300 |
| 19 | 474821679792884860590 |
| 20 | 7992739387298462213340 |