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 | 3 |
| 4 | 7 |
| 5 | 21 |
| 6 | 60 |
| 7 | 190 |
| 8 | 600 |
| 9 | 1977 |
| 10 | 6589 |
| 11 | 22408 |
| 12 | 77050 |
| 13 | 268178 |
| 14 | 941599 |
| 15 | 3333585 |
| 16 | 11882427 |
| 17 | 42615480 |
| 18 | 153653039 |
| 19 | 556664752 |
| 20 | 2025330509 |
| 21 | 7397242875 |
| 22 | 27111563026 |
| 23 | 99681629658 |
| 24 | 367563272278 |
| 25 | 1358945378906 |
| 26 | 5036549490009 |
| 27 | 18708739990129 |
| 28 | 69640873691941 |