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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 61 |
| 6 | 199 |
| 7 | 661 |
| 8 | 2234 |
| 9 | 7668 |
| 10 | 26674 |
| 11 | 93858 |
| 12 | 333524 |
| 13 | 1195288 |
| 14 | 4315468 |
| 15 | 15681838 |
| 16 | 57312643 |
| 17 | 210529213 |
| 18 | 776872243 |
| 19 | 2878482523 |
| 20 | 10704933793 |
| 21 | 39945106573 |
| 22 | 149511432793 |
| 23 | 561182969173 |
| 24 | 2111812422871 |
| 25 | 7965992783803 |
| 26 | 30114859723751 |
| 27 | 114079902339303 |
| 28 | 432975153092011 |
| 29 | 1646215731143667 |