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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 998 |
| 5 | 51618 |
| 6 | 873852 |
| 7 | 8039322 |
| 8 | 50272978 |
| 9 | 240764814 |
| 10 | 947860554 |
| 11 | 3210392210 |
| 12 | 9649651136 |
| 13 | 26316155354 |
| 14 | 66191981440 |
| 15 | 155482089002 |
| 16 | 344411086374 |
| 17 | 725043524246 |
| 18 | 1459722296638 |
| 19 | 2825136685698 |
| 20 | 5278863810724 |
| 21 | 9557560367842 |