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 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 30 |
| 5 | 101 |
| 6 | 394 |
| 7 | 1760 |
| 8 | 8970 |
| 9 | 51368 |
| 10 | 326991 |
| 11 | 2289669 |
| 12 | 17491625 |
| 13 | 144760655 |
| 14 | 1290204758 |
| 15 | 12320541392 |
| 16 | 125496010615 |
| 17 | 1358185050788 |
| 18 | 15563654383395 |
| 19 | 188254471337718 |
| 20 | 2396930376564860 |
| 21 | 32044598671291610 |