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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 27 |
| 5 | 159 |
| 6 | 1154 |
| 7 | 9968 |
| 8 | 99861 |
| 9 | 1138234 |
| 10 | 14544650 |
| 11 | 205927012 |
| 12 | 3199714508 |
| 13 | 54131864317 |
| 14 | 990455375968 |
| 15 | 19488387266842 |
| 16 | 410328328297512 |
| 17 | 9205128127109576 |
| 18 | 219191041679766542 |
| 19 | 5521387415218119528 |
| 20 | 146689867860276432637 |
| 21 | 4099255234885039058842 |
| 22 | 120199458455807733040338 |