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 | 13 |
| 3 | 47 |
| 4 | 259 |
| 5 | 1189 |
| 6 | 5877 |
| 7 | 28167 |
| 8 | 136723 |
| 9 | 660173 |
| 10 | 3194613 |
| 11 | 15445007 |
| 12 | 74699811 |
| 13 | 361230229 |
| 14 | 1746933205 |
| 15 | 8448061879 |
| 16 | 40854753875 |
| 17 | 197572345789 |
| 18 | 955455626773 |
| 19 | 4620559362303 |
| 20 | 22344915889827 |
| 21 | 108059470995013 |
| 22 | 522573007884725 |
| 23 | 2527150465444071 |
| 24 | 12221238828079379 |