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 | 15 |
| 2 | 150 |
| 3 | 1175 |
| 4 | 7875 |
| 5 | 46953 |
| 6 | 255745 |
| 7 | 1293825 |
| 8 | 6154530 |
| 9 | 27772930 |
| 10 | 119720802 |
| 11 | 495673410 |
| 12 | 1979777985 |
| 13 | 7656005115 |
| 14 | 28752006375 |
| 15 | 105129718102 |
| 16 | 375082371420 |
| 17 | 1308260532180 |
| 18 | 4468338006465 |