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 | 34 |
| 3 | 280 |
| 4 | 2146 |
| 5 | 15784 |
| 6 | 113554 |
| 7 | 807160 |
| 8 | 5699266 |
| 9 | 40091464 |
| 10 | 281426674 |
| 11 | 1973132440 |
| 12 | 13824509986 |
| 13 | 96821901544 |
| 14 | 677954637394 |
| 15 | 4746487768120 |
| 16 | 33228635602306 |
| 17 | 232613334118024 |
| 18 | 1628344878433714 |
| 19 | 11398620307466200 |