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 | 3 |
| 3 | 15 |
| 4 | 104 |
| 5 | 909 |
| 6 | 9449 |
| 7 | 112398 |
| 8 | 1489410 |
| 9 | 21562086 |
| 10 | 336086022 |
| 11 | 5577242292 |
| 12 | 97671172836 |
| 13 | 1792348213025 |
| 14 | 34268124834495 |
| 15 | 679376016769260 |
| 16 | 13911118850603610 |
| 17 | 293220749128031010 |