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 | 28 |
| 4 | 233 |
| 5 | 2376 |
| 6 | 28102 |
| 7 | 379016 |
| 8 | 5707025 |
| 9 | 94439440 |
| 10 | 1699067321 |
| 11 | 32951077193 |
| 12 | 684009742319 |
| 13 | 15110032165151 |
| 14 | 353485501643471 |
| 15 | 8721374385748256 |
| 16 | 226128389777924385 |
| 17 | 6142306518887606112 |
| 18 | 174311816444805024379 |