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 | 5 |
| 3 | 18 |
| 4 | 70 |
| 5 | 323 |
| 6 | 1683 |
| 7 | 9690 |
| 8 | 59917 |
| 9 | 388894 |
| 10 | 2606742 |
| 11 | 17869870 |
| 12 | 124516636 |
| 13 | 878591340 |