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 | 3 |
| 2 | 15 |
| 3 | 117 |
| 4 | 1185 |
| 5 | 15123 |
| 6 | 230895 |
| 7 | 4116837 |
| 8 | 83860545 |
| 9 | 1921996323 |
| 10 | 48942778575 |
| 11 | 1370953667157 |
| 12 | 41893214676705 |
| 13 | 1386843017916723 |
| 14 | 49441928730798255 |
| 15 | 1888542637550347077 |
| 16 | 76946148390480577665 |
| 17 | 3331009898404800736323 |
| 18 | 152682246738275154625935 |
| 19 | 7387240827905368219116597 |