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 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 134 |
| 5 | 1935 |
| 6 | 20830 |
| 7 | 198303 |
| 8 | 1776894 |
| 9 | 15402495 |
| 10 | 130890110 |
| 11 | 1098087903 |
| 12 | 9130126654 |
| 13 | 75412301055 |
| 14 | 619706950590 |
| 15 | 5071742430303 |
| 16 | 41369422556414 |
| 17 | 336511166127615 |
| 18 | 2730929153686270 |
| 19 | 22119108433729503 |
| 20 | 178853777028618174 |