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 | 4 |
| 3 | 14 |
| 4 | 60 |
| 5 | 267 |
| 6 | 1254 |
| 7 | 6071 |
| 8 | 30156 |
| 9 | 152714 |
| 10 | 785682 |
| 11 | 4094752 |
| 12 | 21573258 |
| 13 | 114709363 |
| 14 | 614777462 |
| 15 | 3317589966 |
| 16 | 18011350796 |
| 17 | 98307220409 |
| 18 | 539121535194 |
| 19 | 2969177051678 |
| 20 | 16415395615190 |
| 21 | 91070109305056 |
| 22 | 506843759000184 |
| 23 | 2828968117483929 |
| 24 | 15831944500607010 |
| 25 | 88818114923080102 |