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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 15 |
| 5 | 206 |
| 6 | 2682 |
| 7 | 27170 |
| 8 | 257548 |
| 9 | 2367474 |
| 10 | 21487314 |
| 11 | 194202685 |
| 12 | 1754011594 |
| 13 | 15861755259 |
| 14 | 143759801949 |
| 15 | 1306540582093 |
| 16 | 11910121180550 |
| 17 | 108905308434147 |
| 18 | 998874124565038 |