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 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 19 |
| 6 | 96 |
| 7 | 511 |
| 8 | 2832 |
| 9 | 16215 |
| 10 | 95374 |
| 11 | 573837 |
| 12 | 3520228 |
| 13 | 21961119 |
| 14 | 139038824 |
| 15 | 891817687 |
| 16 | 5787091552 |
| 17 | 37946582995 |
| 18 | 251173847170 |
| 19 | 1676831257693 |
| 20 | 11282156358500 |
| 21 | 76453813499219 |
| 22 | 521508969157826 |
| 23 | 3578990500062417 |
| 24 | 24700214881378152 |
| 25 | 171359711873508367 |