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 | 9 |
| 2 | 55 |
| 3 | 285 |
| 4 | 1351 |
| 5 | 6069 |
| 6 | 26335 |
| 7 | 111645 |
| 8 | 465751 |
| 9 | 1921029 |
| 10 | 7859215 |
| 11 | 31964205 |
| 12 | 129442951 |
| 13 | 522538389 |
| 14 | 2104469695 |
| 15 | 8460859965 |
| 16 | 33972448951 |
| 17 | 136276954149 |
| 18 | 546269553775 |
| 19 | 2188563950925 |
| 20 | 8764714059751 |
| 21 | 35090233104309 |
| 22 | 140455067207455 |
| 23 | 562102681589085 |
| 24 | 2249257981411351 |