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 | 13 |
| 3 | 76 |
| 4 | 538 |
| 5 | 4475 |
| 6 | 42690 |
| 7 | 460078 |
| 8 | 5529599 |
| 9 | 73363513 |
| 10 | 1065232928 |
| 11 | 16805164107 |
| 12 | 286272028319 |
| 13 | 5237527189339 |
| 14 | 102436515541828 |
| 15 | 2132945295370361 |
| 16 | 47110759618985100 |
| 17 | 1100186748111381882 |
| 18 | 27086589720802913597 |
| 19 | 701202975449809856301 |