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 | 2 |
| 4 | 8 |
| 5 | 30 |
| 6 | 103 |
| 7 | 368 |
| 8 | 1407 |
| 9 | 5531 |
| 10 | 21905 |
| 11 | 87689 |
| 12 | 355929 |
| 13 | 1461022 |
| 14 | 6046160 |
| 15 | 25194331 |
| 16 | 105661615 |
| 17 | 445692621 |
| 18 | 1889454880 |
| 19 | 8045796200 |
| 20 | 34398989998 |
| 21 | 147606568810 |
| 22 | 635481458969 |
| 23 | 2744158752772 |
| 24 | 11882687400375 |
| 25 | 51584960268914 |
| 26 | 224465280616995 |
| 27 | 978851595046223 |