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 | 4 |
| 3 | 26 |
| 4 | 234 |
| 5 | 2696 |
| 6 | 37919 |
| 7 | 630521 |
| 8 | 12111114 |
| 9 | 264051201 |
| 10 | 6445170229 |
| 11 | 174183891471 |
| 12 | 5164718385337 |
| 13 | 166737090160871 |
| 14 | 5822980248613990 |
| 15 | 218756388226681557 |
| 16 | 8797723991458469015 |
| 17 | 377159237609540937788 |
| 18 | 17170729962232112834302 |
| 19 | 827382365085791968518198 |
| 20 | 42070004707327023844695198 |