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 | 2 |
| 4 | 6 |
| 5 | 17 |
| 6 | 53 |
| 7 | 205 |
| 8 | 871 |
| 9 | 3876 |
| 10 | 18820 |
| 11 | 99585 |
| 12 | 558847 |
| 13 | 3313117 |
| 14 | 20825145 |
| 15 | 138046940 |
| 16 | 959298572 |
| 17 | 6974868139 |
| 18 | 52972352923 |
| 19 | 419104459913 |
| 20 | 3446343893607 |
| 21 | 29405917751526 |
| 22 | 259930518212766 |
| 23 | 2376498296500063 |
| 24 | 22441988298860757 |
| 25 | 218615700758838253 |