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 | 2 |
| 2 | 1 |
| 3 | 6 |
| 4 | 12 |
| 5 | 35 |
| 6 | 88 |
| 7 | 234 |
| 8 | 609 |
| 9 | 1598 |
| 10 | 4180 |
| 11 | 10947 |
| 12 | 28656 |
| 13 | 75026 |
| 14 | 196417 |
| 15 | 514230 |
| 16 | 1346268 |
| 17 | 3524579 |
| 18 | 9227464 |
| 19 | 24157818 |
| 20 | 63245985 |
| 21 | 165580142 |
| 22 | 433494436 |
| 23 | 1134903171 |
| 24 | 2971215072 |
| 25 | 7778742050 |
| 26 | 20365011073 |
| 27 | 53316291174 |
| 28 | 139583862444 |
| 29 | 365435296163 |
| 30 | 956722026040 |
| 31 | 2504730781962 |