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 | 1 |
| 3 | 53 |
| 4 | 486 |
| 5 | 4091 |
| 6 | 32070 |
| 7 | 246852 |
| 8 | 1897509 |
| 9 | 14578434 |
| 10 | 112390406 |
| 11 | 867693603 |
| 12 | 6716080364 |
| 13 | 52061270779 |
| 14 | 404329966577 |
| 15 | 3144612848086 |
| 16 | 24493415901992 |
| 17 | 191015933608631 |
| 18 | 1491484435347360 |
| 19 | 11658153191250672 |
| 20 | 91217811828544156 |