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 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 36 |
| 4 | 232 |
| 5 | 1585 |
| 6 | 11298 |
| 7 | 83097 |
| 8 | 625992 |
| 9 | 4805595 |
| 10 | 37458330 |
| 11 | 295673994 |
| 12 | 2358641376 |
| 13 | 18985057351 |
| 14 | 154000562758 |
| 15 | 1257643249140 |
| 16 | 10331450919456 |
| 17 | 85317692667643 |
| 18 | 707854577312178 |
| 19 | 5897493615536452 |
| 20 | 49320944483427000 |
| 21 | 413887836110423787 |
| 22 | 3484084625456932134 |
| 23 | 29412628894558563849 |