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 | 6 |
| 4 | 24 |
| 5 | 106 |
| 6 | 470 |
| 7 | 2038 |
| 8 | 8624 |
| 9 | 35754 |
| 10 | 145902 |
| 11 | 588358 |
| 12 | 2351910 |
| 13 | 9341814 |
| 14 | 36936146 |
| 15 | 145567966 |
| 16 | 572415344 |
| 17 | 2247578314 |
| 18 | 8816986046 |
| 19 | 34570684966 |
| 20 | 135522530174 |
| 21 | 531285354214 |
| 22 | 2083180354466 |
| 23 | 8170672802686 |
| 24 | 32059325714054 |
| 25 | 125845764142006 |
| 26 | 494223989283650 |