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) |
|---|---|
| 2 | 1 |
| 3 | 4 |
| 4 | 22 |
| 5 | 141 |
| 6 | 988 |
| 7 | 7337 |
| 8 | 56749 |
| 9 | 452332 |
| 10 | 3689697 |
| 11 | 30652931 |
| 12 | 258465558 |
| 13 | 2206330790 |
| 14 | 19029531220 |
| 15 | 165582392070 |
| 16 | 1451789520435 |
| 17 | 12813638048184 |
| 18 | 113755675163767 |
| 19 | 1015119850103821 |
| 20 | 9100463691522759 |
| 21 | 81923222827031025 |