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 | 108 |
| 4 | 1029 |
| 5 | 12288 |
| 6 | 177147 |
| 7 | 3000000 |
| 8 | 58461513 |
| 9 | 1289945088 |
| 10 | 31813498119 |
| 11 | 867763964928 |
| 12 | 25949267578125 |
| 13 | 844424930131968 |
| 14 | 29713734098717811 |
| 15 | 1124440102746243072 |
| 16 | 45543381089624394897 |
| 17 | 1966080000000000000000 |
| 18 | 90125827485245075684223 |
| 19 | 4372496892684322588065792 |