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 | 3 |
| 2 | 6 |
| 3 | 12 |
| 4 | 26 |
| 5 | 55 |
| 6 | 115 |
| 7 | 239 |
| 8 | 498 |
| 9 | 1038 |
| 10 | 2162 |
| 11 | 4502 |
| 12 | 9375 |
| 13 | 19523 |
| 14 | 40655 |
| 15 | 84659 |
| 16 | 176292 |
| 17 | 367107 |
| 18 | 764456 |
| 19 | 1591886 |
| 20 | 3314907 |
| 21 | 6902887 |
| 22 | 14374415 |
| 23 | 29932954 |
| 24 | 62331700 |
| 25 | 129798109 |
| 26 | 270288619 |
| 27 | 562842849 |
| 28 | 1172051097 |
| 29 | 2440652442 |
| 30 | 5082358916 |