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 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 131 |
| 7 | 420 |
| 8 | 1375 |
| 9 | 4576 |
| 10 | 15431 |
| 11 | 52603 |
| 12 | 180957 |
| 13 | 627340 |
| 14 | 2189430 |
| 15 | 7685785 |
| 16 | 27118855 |
| 17 | 96123508 |
| 18 | 342099955 |
| 19 | 1221979374 |
| 20 | 4379357895 |
| 21 | 15742077045 |
| 22 | 56742085710 |
| 23 | 205041235750 |
| 24 | 742647580815 |
| 25 | 2695585363122 |
| 26 | 9803561513316 |
| 27 | 35720226039252 |
| 28 | 130373533268780 |