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 | 2 |
| 2 | 6 |
| 3 | 13 |
| 4 | 30 |
| 5 | 62 |
| 6 | 133 |
| 7 | 270 |
| 8 | 558 |
| 9 | 1125 |
| 10 | 2286 |
| 11 | 4590 |
| 12 | 9253 |
| 13 | 18542 |
| 14 | 37230 |
| 15 | 74533 |
| 16 | 149358 |
| 17 | 298862 |
| 18 | 598309 |
| 19 | 1196910 |
| 20 | 2394990 |
| 21 | 4790565 |
| 22 | 9583470 |
| 23 | 19168110 |
| 24 | 38340901 |
| 25 | 76684142 |
| 26 | 153377646 |
| 27 | 306759973 |
| 28 | 613538670 |
| 29 | 1227086702 |
| 30 | 2454210853 |