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 | 5 |
| 2 | 33 |
| 3 | 249 |
| 4 | 2033 |
| 5 | 17485 |
| 6 | 156033 |
| 7 | 1431281 |
| 8 | 13412193 |
| 9 | 127840085 |
| 10 | 1235575201 |
| 11 | 12080678505 |
| 12 | 119276490193 |
| 13 | 1187542872989 |
| 14 | 11909326179841 |
| 15 | 120191310803937 |
| 16 | 1219780566014657 |
| 17 | 12440630635406245 |
| 18 | 127446349676475425 |
| 19 | 1310820823328281561 |
| 20 | 13530833791486094769 |