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 | 1 |
| 2 | 5 |
| 3 | 36 |
| 4 | 338 |
| 5 | 3898 |
| 6 | 53173 |
| 7 | 835992 |
| 8 | 14864340 |
| 9 | 294606273 |
| 10 | 6434871231 |
| 11 | 153473830678 |
| 12 | 3966604562709 |
| 13 | 110386840008838 |
| 14 | 3289768253831145 |
| 15 | 104502173165838799 |
| 16 | 3523895395660532937 |
| 17 | 125689588963370029163 |
| 18 | 4726867751402704638366 |
| 19 | 186902021178952943036080 |