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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 23 |
| 4 | 97 |
| 5 | 399 |
| 6 | 1617 |
| 7 | 6511 |
| 8 | 26129 |
| 9 | 104687 |
| 10 | 419089 |
| 11 | 1677039 |
| 12 | 6709521 |
| 13 | 26840815 |
| 14 | 107368721 |
| 15 | 429485807 |
| 16 | 1717965073 |
| 17 | 6871903983 |
| 18 | 27487703313 |
| 19 | 109950988015 |
| 20 | 439804301585 |
| 21 | 1759217905391 |
| 22 | 7036873019665 |
| 23 | 28147494874863 |