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 | 8 |
| 2 | 56 |
| 3 | 392 |
| 4 | 2696 |
| 5 | 18584 |
| 6 | 127160 |
| 7 | 871256 |
| 8 | 5946200 |
| 9 | 40613816 |
| 10 | 276750536 |
| 11 | 1886784200 |
| 12 | 12843449288 |
| 13 | 87456597656 |
| 14 | 594876193016 |
| 15 | 4047352264616 |
| 16 | 27514497698984 |
| 17 | 187083712725224 |
| 18 | 1271271096363128 |
| 19 | 8639846411760440 |
| 20 | 58689235680164600 |
| 21 | 398715967140863864 |