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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 13 |
| 7 | 34 |
| 8 | 110 |
| 9 | 393 |
| 10 | 1449 |
| 11 | 5390 |
| 12 | 21534 |
| 13 | 90418 |
| 14 | 389265 |
| 15 | 1694769 |
| 16 | 7593330 |
| 17 | 34910142 |
| 18 | 163314286 |
| 19 | 772044618 |
| 20 | 3702870682 |
| 21 | 18017064221 |
| 22 | 88689351909 |
| 23 | 440271808570 |
| 24 | 2205020557614 |
| 25 | 11141413883818 |
| 26 | 56737939027682 |