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 | 8 |
| 3 | 85 |
| 4 | 988 |
| 5 | 10696 |
| 6 | 104676 |
| 7 | 939863 |
| 8 | 7980376 |
| 9 | 65679175 |
| 10 | 532115106 |
| 11 | 4279710436 |
| 12 | 34311898336 |
| 13 | 274729437763 |
| 14 | 2198561705222 |
| 15 | 17590732383423 |
| 16 | 140732804110800 |
| 17 | 1125884352801489 |
| 18 | 9007145852828686 |
| 19 | 72057404552774828 |
| 20 | 576460059887430848 |
| 21 | 4611683426113781209 |