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 | 1 |
| 2 | 5 |
| 3 | 41 |
| 4 | 477 |
| 5 | 7201 |
| 6 | 133685 |
| 7 | 2945881 |
| 8 | 75145677 |
| 9 | 2177900241 |
| 10 | 70687244965 |
| 11 | 2539879312521 |
| 12 | 100086803174077 |
| 13 | 4291845333310081 |
| 14 | 198954892070938645 |
| 15 | 9914294755149067961 |
| 16 | 528504758009562261677 |
| 17 | 30010032597449931644721 |
| 18 | 1808359960001658961070725 |