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 | -3 |
| 2 | 3 |
| 3 | 1 |
| 4 | 3 |
| 5 | 3 |
| 6 | 7 |
| 7 | 9 |
| 8 | 99 |
| 9 | 143 |
| 10 | 429 |
| 11 | 663 |
| 12 | 4199 |
| 13 | 6783 |
| 14 | 22287 |
| 15 | 37145 |
| 16 | 1002915 |
| 17 | 1710855 |
| 18 | 5892945 |
| 19 | 10235115 |
| 20 | 71645805 |
| 21 | 126233085 |
| 22 | 447553665 |
| 23 | 797813055 |
| 24 | 11435320455 |
| 25 | 20583576819 |
| 26 | 74417546961 |
| 27 | 135054066707 |
| 28 | 983965343151 |
| 29 | 1798281489207 |
| 30 | 6593698793759 |
| 31 | 12123897782073 |