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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 78 |
| 6 | 313 |
| 7 | 1306 |
| 8 | 5653 |
| 9 | 25088 |
| 10 | 113685 |
| 11 | 523522 |
| 12 | 2443590 |
| 13 | 11533010 |
| 14 | 54949539 |
| 15 | 263933658 |
| 16 | 1276652682 |
| 17 | 6213207330 |
| 18 | 30402727854 |
| 19 | 149486487326 |
| 20 | 738184395770 |
| 21 | 3659440942282 |
| 22 | 18205043615467 |
| 23 | 90856842218506 |
| 24 | 454770531433586 |
| 25 | 2282393627458496 |
| 26 | 11483114908752959 |