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 | 20 |
| 2 | 400 |
| 3 | 5029 |
| 4 | 44803 |
| 5 | 308470 |
| 6 | 1738756 |
| 7 | 8350154 |
| 8 | 35158856 |
| 9 | 132595894 |
| 10 | 455284536 |
| 11 | 1441678804 |
| 12 | 4253578398 |
| 13 | 11791889562 |
| 14 | 30929283640 |
| 15 | 77204065141 |
| 16 | 184304047745 |
| 17 | 422556706314 |
| 18 | 933834642586 |
| 19 | 1995549087157 |
| 20 | 4134881948947 |
| 21 | 8327774224280 |