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 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 51 |
| 6 | 271 |
| 7 | 1366 |
| 8 | 8849 |
| 9 | 58717 |
| 10 | 432541 |
| 11 | 3530176 |
| 12 | 29787781 |
| 13 | 279974839 |
| 14 | 2715912291 |
| 15 | 28415168146 |
| 16 | 312503079841 |
| 17 | 3600714035321 |
| 18 | 43979791574809 |
| 19 | 556150585730140 |
| 20 | 7417561518005341 |
| 21 | 102438949373356891 |
| 22 | 1476634705941320311 |
| 23 | 22102618328057267694 |