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 | 6 |
| 4 | 24 |
| 5 | 109 |
| 6 | 588 |
| 7 | 3654 |
| 8 | 26125 |
| 9 | 209863 |
| 10 | 1876502 |
| 11 | 18441367 |
| 12 | 197776850 |
| 13 | 2297242583 |
| 14 | 28739304385 |
| 15 | 385195455471 |
| 16 | 5507210188401 |
| 17 | 83657067537498 |
| 18 | 1345556172013026 |
| 19 | 22844387886649418 |
| 20 | 408258252653717337 |
| 21 | 7660885499702743124 |
| 22 | 150600621665021781932 |