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 | -1 |
| 1 | -1 |
| 2 | 1 |
| 3 | 8 |
| 4 | 23 |
| 5 | 64 |
| 6 | 479 |
| 7 | 6026 |
| 8 | 80863 |
| 9 | 1194488 |
| 10 | 19951919 |
| 11 | 374005774 |
| 12 | 7768598111 |
| 13 | 177019006748 |
| 14 | 4389955280983 |
| 15 | 117700126685714 |
| 16 | 3392361648663359 |
| 17 | 104592876994535056 |
| 18 | 3434908279968850463 |
| 19 | 119702402510430502358 |
| 20 | 4411764405014665620799 |