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 | 3 |
| 2 | 22 |
| 3 | 131 |
| 4 | 823 |
| 5 | 5096 |
| 6 | 31687 |
| 7 | 196785 |
| 8 | 1222550 |
| 9 | 7594361 |
| 10 | 47177097 |
| 11 | 293066688 |
| 12 | 1820552297 |
| 13 | 11309395995 |
| 14 | 70254767718 |
| 15 | 436427542283 |
| 16 | 2711118571311 |
| 17 | 16841658983944 |
| 18 | 104621568809247 |
| 19 | 649916534985369 |
| 20 | 4037327172325542 |