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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 7 |
| 5 | 50 |
| 6 | 254 |
| 7 | 1245 |
| 8 | 5898 |
| 9 | 29600 |
| 10 | 163705 |
| 11 | 925977 |
| 12 | 5690175 |
| 13 | 36681963 |
| 14 | 241663896 |
| 15 | 1662446097 |
| 16 | 12134853382 |
| 17 | 93406989325 |
| 18 | 730785520398 |
| 19 | 5990426525483 |
| 20 | 50538885715526 |
| 21 | 432266550168097 |
| 22 | 3845700235189327 |
| 23 | 35065304557027821 |
| 24 | 334652745159828239 |
| 25 | 3262707438761612651 |