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 | 7 |
| 3 | 33 |
| 4 | 715 |
| 5 | 4199 |
| 6 | 52003 |
| 7 | 334305 |
| 8 | 17678835 |
| 9 | 119409675 |
| 10 | 1641030105 |
| 11 | 11435320455 |
| 12 | 322476036831 |
| 13 | 2295919134019 |
| 14 | 32968493968795 |
| 15 | 238436656380769 |
| 16 | 27767032438524099 |
| 17 | 203236010537432691 |
| 18 | 2989949596465113373 |