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 | 2 |
| 2 | 9 |
| 3 | 38 |
| 4 | 185 |
| 5 | 914 |
| 6 | 4706 |
| 7 | 24632 |
| 8 | 131309 |
| 9 | 708284 |
| 10 | 3861380 |
| 11 | 21225588 |
| 12 | 117511456 |
| 13 | 654474352 |
| 14 | 3664017964 |
| 15 | 20604973852 |
| 16 | 116332926949 |
| 17 | 659097637368 |
| 18 | 3745842085016 |
| 19 | 21348227213714 |
| 20 | 121974246173946 |
| 21 | 698499504058204 |