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 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 67 |
| 6 | 305 |
| 7 | 2359 |
| 8 | 16495 |
| 9 | 141643 |
| 10 | 1273691 |
| 11 | 15580299 |
| 12 | 152788607 |
| 13 | 2206382433 |
| 14 | 28916044241 |
| 15 | 399450183613 |