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 | 17 |
| 4 | 119 |
| 5 | 1509 |
| 6 | 18799 |
| 7 | 342397 |
| 8 | 6340263 |
| 9 | 151918421 |
| 10 | 4619754311 |
| 11 | 140219120601 |
| 12 | 5396354613583 |
| 13 | 221721908976697 |
| 14 | 9431597787000999 |
| 15 | 447473598316521449 |
| 16 | 24163152239530299719 |
| 17 | 1444153946379288324477 |
| 18 | 87200644323074509092943 |
| 19 | 5929294512595059362045041 |