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 | 5 |
| 8 | 27 |
| 9 | 175 |
| 10 | 1533 |
| 11 | 14361 |
| 12 | 151575 |
| 13 | 1735869 |
| 14 | 21594863 |
| 15 | 289365383 |
| 16 | 4158887007 |
| 17 | 63822480809 |
| 18 | 1041820050629 |
| 19 | 18027531255745 |
| 20 | 329658402237171 |
| 21 | 6352776451924233 |
| 22 | 128686951765990343 |
| 23 | 2733851297673484765 |
| 24 | 60781108703102022027 |
| 25 | 1411481990523638719737 |