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 | 1 |
| 1 | 4 |
| 2 | 29 |
| 3 | 232 |
| 4 | 1941 |
| 5 | 16664 |
| 6 | 145499 |
| 7 | 1285624 |
| 8 | 11460949 |
| 9 | 102875128 |
| 10 | 928495764 |
| 11 | 8417689504 |
| 12 | 76599066579 |
| 13 | 699232769512 |
| 14 | 6400175653922 |
| 15 | 58718827590992 |
| 16 | 539822826733397 |
| 17 | 4971747032359352 |
| 18 | 45863130731297180 |
| 19 | 423683961417124576 |
| 20 | 3919058645835901556 |