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 | 4 |
| 7 | 29 |
| 8 | 424 |
| 9 | 15471 |
| 10 | 1249972 |
| 11 | 187095836 |
| 12 | 48211095992 |
| 13 | 21124789189703 |
| 14 | 15899588477573380 |
| 15 | 20900616544566305160 |
| 16 | 48843531771541430977365 |
| 17 | 206305644374013971584957120 |
| 18 | 1597725697294349735784472597650 |
| 19 | 22957145992821363656862872542094876 |
| 20 | 617791721556546579087246090934406095676 |