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 | 1 |
| 2 | 6 |
| 3 | 31 |
| 4 | 166 |
| 5 | 931 |
| 6 | 5412 |
| 7 | 32334 |
| 8 | 197378 |
| 9 | 1225871 |
| 10 | 7722282 |
| 11 | 49224175 |
| 12 | 316921948 |
| 13 | 2057994779 |
| 14 | 13463417108 |
| 15 | 88650225829 |
| 16 | 587062025226 |
| 17 | 3907415784953 |
| 18 | 26125388534522 |
| 19 | 175389933980744 |
| 20 | 1181803269037438 |
| 21 | 7989829660805193 |