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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 117 |
| 5 | 1367 |
| 6 | 23329 |
| 7 | 570933 |
| 8 | 19740068 |
| 9 | 951916938 |
| 10 | 63295826369 |
| 11 | 5743788894259 |
| 12 | 704672958229270 |
| 13 | 115877288304781885 |
| 14 | 25338423080304873558 |
| 15 | 7313716095786704678585 |
| 16 | 2767636572798780219442327 |
| 17 | 1364367542961142350256304582 |
| 18 | 871016593387715393187604249892 |