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 | 3 |
| 1 | 13 |
| 2 | 61 |
| 3 | 307 |
| 4 | 1633 |
| 5 | 9043 |
| 6 | 51481 |
| 7 | 298507 |
| 8 | 1751713 |
| 9 | 10359523 |
| 10 | 61573801 |
| 11 | 367168507 |
| 12 | 2194090993 |
| 13 | 13129397203 |
| 14 | 78637382521 |
| 15 | 471273075307 |
| 16 | 2825447921473 |
| 17 | 16943968454083 |
| 18 | 101629063565641 |
| 19 | 609635780178907 |