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 | 6 |
| 2 | 15 |
| 3 | 51 |
| 4 | 754 |
| 5 | 803 |
| 6 | 2160 |
| 7 | 3048 |
| 8 | 8315 |
| 9 | 18549 |
| 10 | 27094 |
| 11 | 89929 |
| 12 | 251712 |
| 13 | 505768 |
| 14 | 936240 |
| 15 | 1617182 |
| 16 | 2182656 |
| 17 | 2582372 |
| 18 | 5116884 |
| 19 | 27067121 |
| 20 | 77131559 |