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 | 12 |
| 4 | 30 |
| 5 | 60 |
| 6 | 132 |
| 7 | 264 |
| 8 | 558 |
| 9 | 1116 |
| 10 | 2292 |
| 11 | 4584 |
| 12 | 9300 |
| 13 | 18600 |
| 14 | 37464 |
| 15 | 74928 |
| 16 | 150414 |
| 17 | 300828 |
| 18 | 602772 |
| 19 | 1205544 |
| 20 | 2413380 |
| 21 | 4826760 |
| 22 | 9658104 |
| 23 | 19316208 |
| 24 | 38641716 |
| 25 | 77283432 |
| 26 | 154585464 |
| 27 | 309170928 |
| 28 | 618379320 |
| 29 | 1236758640 |
| 30 | 2473592208 |
| 31 | 4947184416 |
| 32 | 9894519246 |
| 33 | 19789038492 |
| 34 | 39578377812 |