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 | 3 |
| 3 | 10 |
| 4 | 63 |
| 5 | 558 |
| 6 | 6226 |
| 7 | 82836 |
| 8 | 1272555 |
| 9 | 22103638 |
| 10 | 427715118 |
| 11 | 9118752300 |
| 12 | 212335628550 |
| 13 | 5362040637900 |
| 14 | 145970732893284 |
| 15 | 4261945511044520 |
| 16 | 132868133756374707 |
| 17 | 4405535689300995942 |
| 18 | 154819142574597555670 |