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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 13 |
| 6 | 57 |
| 7 | 271 |
| 8 | 1467 |
| 9 | 8905 |
| 10 | 58965 |
| 11 | 420331 |
| 12 | 3212391 |
| 13 | 26227477 |
| 14 | 227640033 |
| 15 | 2090172631 |
| 16 | 20222758995 |
| 17 | 205524856129 |
| 18 | 2188159483341 |
| 19 | 24344716477411 |
| 20 | 282390978550239 |
| 21 | 3408195810080461 |
| 22 | 42719427069801369 |
| 23 | 555174137978970511 |
| 24 | 7469189351830156683 |