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 | 3 |
| 2 | 75 |
| 3 | 969 |
| 4 | 8964 |
| 5 | 66975 |
| 6 | 429096 |
| 7 | 2442372 |
| 8 | 12640320 |
| 9 | 60454713 |
| 10 | 270391857 |
| 11 | 1141260315 |
| 12 | 4578160257 |
| 13 | 17554638039 |
| 14 | 64642406670 |
| 15 | 229486544439 |
| 16 | 788018124312 |
| 17 | 2624648438025 |
| 18 | 8499852952224 |
| 19 | 26820711864657 |
| 20 | 82613109082410 |