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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 2 |
| 9 | 5 |
| 10 | 15 |
| 11 | 64 |
| 12 | 342 |
| 13 | 2321 |
| 14 | 18578 |
| 15 | 168287 |
| 16 | 1656209 |
| 17 | 17288336 |
| 18 | 188006362 |
| 19 | 2105867058 |
| 20 | 24108331027 |
| 21 | 280638347609 |
| 22 | 3310098377912 |
| 23 | 39462525169310 |
| 24 | 474697793413215 |
| 25 | 5754095507495584 |
| 26 | 70216415130786725 |
| 27 | 861924378411516159 |
| 28 | 10636562125193377459 |