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 | 7 |
| 2 | 49 |
| 3 | 357 |
| 4 | 2695 |
| 5 | 20930 |
| 6 | 166257 |
| 7 | 1344904 |
| 8 | 11042724 |
| 9 | 91801255 |
| 10 | 771201431 |
| 11 | 6536904290 |
| 12 | 55838330730 |
| 13 | 480197194260 |
| 14 | 4154140621425 |
| 15 | 36126361733616 |
| 16 | 315647802951628 |
| 17 | 2769544822393356 |
| 18 | 24392874398953060 |
| 19 | 215582307059144025 |
| 20 | 1911286446370861455 |
| 21 | 16993580092566979770 |
| 22 | 151491588134469616215 |