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 | 3 |
| 3 | 16 |
| 4 | 133 |
| 5 | 1571 |
| 6 | 24721 |
| 7 | 496168 |
| 8 | 12317761 |
| 9 | 369451477 |
| 10 | 13135552831 |
| 11 | 545021905176 |
| 12 | 26051269951213 |
| 13 | 1418976050686351 |
| 14 | 87262518335077541 |
| 15 | 6010361475663954256 |
| 16 | 460405692649973927041 |
| 17 | 38981134670714611635913 |
| 18 | 3627857520994811984369371 |
| 19 | 369309424376334817020139840 |