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 | 2 |
| 4 | 998 |
| 5 | 36698 |
| 6 | 620210 |
| 7 | 5367308 |
| 8 | 34678364 |
| 9 | 169259212 |
| 10 | 682686652 |
| 11 | 2356999994 |
| 12 | 7294368210 |
| 13 | 20227526910 |
| 14 | 52008171998 |
| 15 | 124422857864 |
| 16 | 279767468172 |
| 17 | 596674510744 |
| 18 | 1218556387684 |
| 19 | 2385034544810 |
| 20 | 4509309201242 |