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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 55 |
| 6 | 275 |
| 7 | 1461 |
| 8 | 8121 |
| 9 | 46760 |
| 10 | 276990 |
| 11 | 1679692 |
| 12 | 10388794 |
| 13 | 65348331 |
| 14 | 417122415 |
| 15 | 2696925449 |
| 16 | 17636415027 |
| 17 | 116508178394 |
| 18 | 776713914842 |
| 19 | 5220901613826 |
| 20 | 35357775815996 |
| 21 | 241100774277388 |
| 22 | 1654405307080112 |
| 23 | 11418270330490544 |
| 24 | 79229054480527932 |
| 25 | 552492413404591296 |