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 | 4 |
| 2 | 15 |
| 3 | 49 |
| 4 | 154 |
| 5 | 473 |
| 6 | 1437 |
| 7 | 4340 |
| 8 | 13067 |
| 9 | 39277 |
| 10 | 117954 |
| 11 | 354061 |
| 12 | 1062505 |
| 13 | 3188036 |
| 14 | 9564951 |
| 15 | 28696217 |
| 16 | 86090858 |
| 17 | 258276145 |
| 18 | 774834213 |
| 19 | 2324511988 |
| 20 | 6973551091 |
| 21 | 20920677749 |
| 22 | 62762072850 |
| 23 | 188286282629 |
| 24 | 564858951569 |
| 25 | 1694577022468 |