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 | 12 |
| 1 | 25 |
| 2 | 77 |
| 3 | 319 |
| 4 | 1577 |
| 5 | 8575 |
| 6 | 48977 |
| 7 | 286759 |
| 8 | 1699817 |
| 9 | 10137775 |
| 10 | 60645377 |
| 11 | 363332599 |
| 12 | 2178384857 |
| 13 | 13065493375 |
| 14 | 78378545777 |
| 15 | 470228096839 |
| 16 | 2821239178697 |
| 17 | 16927047127375 |
| 18 | 101561119454177 |
| 19 | 609363227843479 |
| 20 | 3656168902513337 |
| 21 | 21936982025631775 |