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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 6 |
| 4 | 17 |
| 5 | 59 |
| 6 | 204 |
| 7 | 750 |
| 8 | 2746 |
| 9 | 10215 |
| 10 | 37936 |
| 11 | 141468 |
| 12 | 527283 |
| 13 | 1967449 |
| 14 | 7340090 |
| 15 | 27392124 |
| 16 | 102219380 |
| 17 | 381482477 |
| 18 | 1423676862 |
| 19 | 5313214098 |
| 20 | 19829053909 |
| 21 | 74002960983 |
| 22 | 276182321224 |
| 23 | 1030726172586 |
| 24 | 3846720619566 |
| 25 | 14356155740947 |
| 26 | 53577895814828 |
| 27 | 199955425410792 |