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 | 0 |
| 1 | 3 |
| 2 | 57 |
| 3 | 819 |
| 4 | 10545 |
| 5 | 128283 |
| 6 | 1509417 |
| 7 | 17390019 |
| 8 | 197581665 |
| 9 | 2223729963 |
| 10 | 24863682777 |
| 11 | 276721736019 |
| 12 | 3069708899985 |
| 13 | 33972956330043 |
| 14 | 375351787072137 |
| 15 | 4142063797326819 |
| 16 | 45668254886861505 |
| 17 | 503195228685608523 |
| 18 | 5541902914982749497 |
| 19 | 61014975260338690419 |
| 20 | 671597073427953162225 |