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 | 1 |
| 2 | 1 |
| 3 | 6 |
| 4 | 35 |
| 5 | 290 |
| 6 | 2680 |
| 7 | 26379 |
| 8 | 267598 |
| 9 | 2758016 |
| 10 | 28749456 |
| 11 | 302120154 |
| 12 | 3196299285 |
| 13 | 34007337629 |