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 | 16 |
| 4 | 108 |
| 5 | 834 |
| 6 | 6893 |
| 7 | 58659 |
| 8 | 510839 |
| 9 | 4515301 |
| 10 | 40477023 |
| 11 | 366751460 |
| 12 | 3352789726 |
| 13 | 30877698604 |
| 14 | 286159371452 |
| 15 | 2666303391801 |
| 16 | 24959756192476 |
| 17 | 234610874384116 |
| 18 | 2213224276178123 |
| 19 | 20945897352118544 |
| 20 | 198802912201260034 |
| 21 | 1891788092230264832 |
| 22 | 18044365524165259927 |
| 23 | 172479703095316537972 |