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 | 4 |
| 2 | 27 |
| 3 | 212 |
| 4 | 1785 |
| 5 | 15630 |
| 6 | 140287 |
| 7 | 1280592 |
| 8 | 11833389 |
| 9 | 110360150 |
| 10 | 1036670272 |
| 11 | 9794291556 |
| 12 | 92972640761 |
| 13 | 886023463122 |
| 14 | 8471878678545 |
| 15 | 81236546627920 |
| 16 | 780898417097733 |
| 17 | 7522708492892214 |
| 18 | 72607180401922894 |
| 19 | 701969331508141900 |
| 20 | 6796919869909393140 |