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 | 11 |
| 3 | 63 |
| 4 | 388 |
| 5 | 2484 |
| 6 | 16330 |
| 7 | 109549 |
| 8 | 745851 |
| 9 | 5141513 |
| 10 | 35807609 |
| 11 | 251514544 |
| 12 | 1779289072 |
| 13 | 12663046683 |
| 14 | 90583092779 |
| 15 | 650818310772 |
| 16 | 4693790254019 |
| 17 | 33965214382094 |
| 18 | 246504409256254 |
| 19 | 1793728983702287 |
| 20 | 13083256171763427 |