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 | 6 |
| 3 | 57 |
| 4 | 678 |
| 5 | 9270 |
| 6 | 139968 |
| 7 | 2285073 |
| 8 | 39871926 |
| 9 | 739129374 |
| 10 | 14521778820 |
| 11 | 302421450474 |
| 12 | 6687874784484 |
| 13 | 157491909678168 |
| 14 | 3961138908376692 |
| 15 | 106663881061254465 |
| 16 | 3078671632202791782 |
| 17 | 95213375569840078422 |
| 18 | 3149291101933230285924 |
| 19 | 111073721303120881912686 |