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 | 0 |
| 2 | 0 |
| 3 | 2 |
| 4 | 340 |
| 5 | 9386 |
| 6 | 97580 |
| 7 | 649476 |
| 8 | 3184708 |
| 9 | 12472084 |
| 10 | 41199404 |
| 11 | 119171110 |
| 12 | 309957412 |
| 13 | 739123094 |
| 14 | 1639655452 |
| 15 | 3422020324 |
| 16 | 6778432292 |
| 17 | 12833460256 |
| 18 | 23356032940 |
| 19 | 41051290730 |
| 20 | 69954580804 |