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 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 30 |
| 5 | 176 |
| 6 | 490 |
| 7 | 792 |
| 8 | 31185 |
| 9 | 831820 |
| 10 | 2323520 |
| 11 | 8118264 |
| 12 | 118114304 |
| 13 | 2841940500 |
| 14 | 3163127352 |
| 15 | 684957390936 |
| 16 | 60105349839666544 |
| 17 | 471314064268398780 |
| 18 | 52527070729108240605 |
| 19 | 57601805366500810491219000 |
| 20 | 23127843459154899464880444632250 |