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 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 51 |
| 5 | 187 |
| 6 | 718 |
| 7 | 2844 |
| 8 | 11530 |
| 9 | 47612 |
| 10 | 199576 |
| 11 | 847013 |
| 12 | 3632468 |
| 13 | 15717041 |
| 14 | 68527255 |
| 15 | 300780438 |
| 16 | 1327939406 |
| 17 | 5893299392 |
| 18 | 26275243626 |
| 19 | 117635107818 |
| 20 | 528631769323 |
| 21 | 2383660351991 |
| 22 | 10781500113896 |
| 23 | 48903885040638 |
| 24 | 222400899237943 |
| 25 | 1013841791472632 |