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 | 23 |
| 5 | 105 |
| 6 | 552 |
| 7 | 3276 |
| 8 | 21632 |
| 9 | 157058 |
| 10 | 1241542 |
| 11 | 10599358 |
| 12 | 97078720 |
| 13 | 948631866 |
| 14 | 9844060930 |
| 15 | 108045790170 |
| 16 | 1249891268947 |
| 17 | 15192207346713 |
| 18 | 193489732812832 |
| 19 | 2575819322454708 |
| 20 | 35763019798305487 |
| 21 | 516830453606687539 |
| 22 | 7760160395056532042 |
| 23 | 120860540786892879030 |