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 | 4 |
| 3 | 13 |
| 4 | 53 |
| 5 | 228 |
| 6 | 1037 |
| 7 | 4885 |
| 8 | 23640 |
| 9 | 116793 |
| 10 | 586633 |
| 11 | 2986616 |
| 12 | 15377097 |
| 13 | 79927913 |
| 14 | 418852716 |
| 15 | 2210503285 |
| 16 | 11738292397 |
| 17 | 62673984492 |
| 18 | 336260313765 |
| 19 | 1811960161517 |
| 20 | 9802082905840 |
| 21 | 53213718977777 |
| 22 | 289817858570513 |
| 23 | 1583076422786096 |
| 24 | 8670574105626961 |