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 | 2 |
| 3 | 5 |
| 4 | 19 |
| 5 | 93 |
| 6 | 544 |
| 7 | 3742 |
| 8 | 29514 |
| 9 | 262342 |
| 10 | 2594262 |
| 11 | 28248628 |
| 12 | 335844793 |
| 13 | 4328666216 |
| 14 | 60120364101 |
| 15 | 895125421054 |
| 16 | 14222548356739 |
| 17 | 240203038913808 |
| 18 | 4296965473902564 |
| 19 | 81164903395937307 |
| 20 | 1614279745319197539 |