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 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 70 |
| 5 | 794 |
| 6 | 12055 |
| 7 | 233238 |
| 8 | 5556725 |
| 9 | 158931613 |
| 10 | 5350854707 |
| 11 | 208746406117 |
| 12 | 9315261027289 |
| 13 | 470405726166241 |
| 14 | 26636882237942128 |
| 15 | 1678097862705130667 |
| 16 | 116818375064650241036 |
| 17 | 8932347052564257212796 |
| 18 | 746244486452472386213939 |
| 19 | 67796741482683128375533560 |