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 | 0 |
| 2 | 5 |
| 3 | 8 |
| 4 | 55 |
| 5 | 140 |
| 6 | 633 |
| 7 | 1984 |
| 8 | 7827 |
| 9 | 26676 |
| 10 | 99621 |
| 11 | 351080 |
| 12 | 1283247 |
| 13 | 4583580 |
| 14 | 16611505 |
| 15 | 59652624 |
| 16 | 215457835 |
| 17 | 775371268 |
| 18 | 2796772765 |
| 19 | 10073343672 |
| 20 | 36315180295 |
| 21 | 130843331180 |
| 22 | 471599612393 |
| 23 | 1699398816608 |
| 24 | 6124635653443 |
| 25 | 22071172760532 |
| 26 | 79541846573973 |