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 | 4 |
| 1 | 11 |
| 2 | 25 |
| 3 | 53 |
| 4 | 109 |
| 5 | 221 |
| 6 | 445 |
| 7 | 893 |
| 8 | 1789 |
| 9 | 3581 |
| 10 | 7165 |
| 11 | 14333 |
| 12 | 28669 |
| 13 | 57341 |
| 14 | 114685 |
| 15 | 229373 |
| 16 | 458749 |
| 17 | 917501 |
| 18 | 1835005 |
| 19 | 3670013 |
| 20 | 7340029 |
| 21 | 14680061 |
| 22 | 29360125 |
| 23 | 58720253 |
| 24 | 117440509 |
| 25 | 234881021 |
| 26 | 469762045 |
| 27 | 939524093 |
| 28 | 1879048189 |
| 29 | 3758096381 |