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 | 1 |
| 3 | 19 |
| 4 | 134 |
| 5 | 153 |
| 6 | 287 |
| 7 | 3023 |
| 8 | 163529 |
| 9 | 2619487 |
| 10 | 2783016 |
| 11 | 5402503 |
| 12 | 105430573 |
| 13 | 9494154073 |
| 14 | 237459282398 |
| 15 | 246953436471 |
| 16 | 484412718869 |
| 17 | 13810509564803 |
| 18 | 1740608617884047 |
| 19 | 59194503517622401 |
| 20 | 60935112135506448 |