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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 9 |
| 7 | 31 |
| 8 | 128 |
| 9 | 708 |
| 10 | 4015 |
| 11 | 24865 |
| 12 | 177444 |
| 13 | 1357830 |
| 14 | 11141634 |
| 15 | 99680595 |
| 16 | 953369248 |
| 17 | 9687797896 |
| 18 | 104909705019 |
| 19 | 1202985610821 |
| 20 | 14542305462860 |
| 21 | 185165060805578 |
| 22 | 2476043157780478 |
| 23 | 34673872424313463 |