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 | 1 |
| 2 | 13 |
| 3 | 133 |
| 4 | 1261 |
| 5 | 11605 |
| 6 | 105469 |
| 7 | 953317 |
| 8 | 8596237 |
| 9 | 77431669 |
| 10 | 697147165 |
| 11 | 6275373061 |
| 12 | 56482551853 |
| 13 | 508359743893 |
| 14 | 4575304803901 |
| 15 | 41178011670565 |
| 16 | 370603178776909 |
| 17 | 3335432903959477 |
| 18 | 30018913315504477 |
| 19 | 270170288559017029 |