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 | 6 |
| 3 | 45 |
| 4 | 344 |
| 5 | 2670 |
| 6 | 20886 |
| 7 | 164514 |
| 8 | 1303304 |
| 9 | 10375830 |
| 10 | 82947380 |
| 11 | 665440039 |
| 12 | 5354470860 |
| 13 | 43196001173 |
| 14 | 349254823554 |
| 15 | 2829388506690 |
| 16 | 22961191276080 |
| 17 | 186622811691276 |
| 18 | 1518914831183982 |
| 19 | 12377727000122043 |