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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 12 |
| 6 | 34 |
| 7 | 87 |
| 8 | 302 |
| 9 | 1118 |
| 10 | 5478 |
| 11 | 32302 |
| 12 | 251134 |
| 13 | 2527711 |
| 14 | 33985852 |
| 15 | 611846939 |
| 16 | 14864650923 |
| 17 | 488222721991 |
| 18 | 21712049275197 |
| 19 | 1308300679611468 |
| 20 | 106897965189674290 |
| 21 | 11852113048215107821 |
| 22 | 1784730721403509209214 |
| 23 | 365323537513403184463272 |