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 | 4 |
| 1 | 13 |
| 2 | 87 |
| 3 | 1027 |
| 4 | 13275 |
| 5 | 155995 |
| 6 | 1789395 |
| 7 | 19523155 |
| 8 | 204330315 |
| 9 | 2081006083 |
| 10 | 20605602003 |
| 11 | 199966727443 |
| 12 | 1908356153955 |
| 13 | 17942429101363 |
| 14 | 166591116531123 |
| 15 | 1529578004981731 |
| 16 | 13917470067182067 |
| 17 | 125565110929591171 |
| 18 | 1124685106917162579 |
| 19 | 10009134886727192611 |