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 | 19 |
| 3 | 151 |
| 4 | 1511 |
| 5 | 18131 |
| 6 | 50767 |
| 7 | 4061359 |
| 8 | 73104463 |
| 9 | 1462089259 |
| 10 | 32165963699 |
| 11 | 30879325151 |
| 12 | 20071561348151 |
| 13 | 562003717748227 |
| 14 | 16860111532446811 |
| 15 | 539523569038297951 |
| 16 | 3668760269460426067 |
| 17 | 660376848502876692059 |
| 18 | 25094320243109314298243 |
| 19 | 1003772809724372571929719 |
| 20 | 42158458008423648021048199 |