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 | 5 |
| 2 | 23 |
| 3 | 104 |
| 4 | 469 |
| 5 | 2115 |
| 6 | 9539 |
| 7 | 43024 |
| 8 | 194053 |
| 9 | 875245 |
| 10 | 3947651 |
| 11 | 17805240 |
| 12 | 80307649 |
| 13 | 362214635 |
| 14 | 1633710407 |
| 15 | 7368586016 |
| 16 | 33234813001 |
| 17 | 149900237685 |
| 18 | 676100727791 |
| 19 | 3049442757256 |
| 20 | 13754017334317 |
| 21 | 62035266076915 |
| 22 | 279800013602699 |
| 23 | 1261992614249520 |
| 24 | 5692013155802701 |