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 | 12 |
| 2 | 55 |
| 3 | 203 |
| 4 | 684 |
| 5 | 2189 |
| 6 | 6773 |
| 7 | 20460 |
| 8 | 60707 |
| 9 | 177631 |
| 10 | 513996 |
| 11 | 1473817 |
| 12 | 4194025 |
| 13 | 11858508 |
| 14 | 33345679 |
| 15 | 93320819 |
| 16 | 260079468 |
| 17 | 722163365 |
| 18 | 1998685277 |
| 19 | 5515470636 |
| 20 | 15180186491 |
| 21 | 41680890247 |
| 22 | 114197428620 |
| 23 | 312260427313 |
| 24 | 852296004049 |
| 25 | 2322415005324 |
| 26 | 6318599122663 |
| 27 | 17166545274395 |