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 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 35 |
| 7 | 108 |
| 8 | 369 |
| 9 | 1285 |
| 10 | 4655 |
| 11 | 17073 |
| 12 | 63600 |
| 13 | 238591 |
| 14 | 901971 |
| 15 | 3426576 |
| 16 | 13079255 |
| 17 | 50107909 |
| 18 | 192622052 |
| 19 | 742624232 |
| 20 | 2870671950 |
| 21 | 11123060678 |
| 22 | 43191857688 |
| 23 | 168047007728 |
| 24 | 654999700403 |
| 25 | 2557227044764 |
| 26 | 9999088822075 |
| 27 | 39153010938487 |
| 28 | 153511100594603 |