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 | 21 |
| 3 | 56 |
| 4 | 781 |
| 5 | 2415 |
| 6 | 31529 |
| 7 | 100352 |
| 8 | 1292697 |
| 9 | 4140081 |
| 10 | 53175517 |
| 11 | 170537640 |
| 12 | 2188978117 |
| 13 | 7022359583 |
| 14 | 90124167441 |
| 15 | 289143013376 |
| 16 | 3710708201969 |
| 17 | 11905151192865 |
| 18 | 152783289861989 |
| 19 | 490179860527896 |
| 20 | 6290652543875133 |