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 | 1 |
| 2 | 3 |
| 3 | 143 |
| 4 | 285 |
| 5 | 569 |
| 6 | 683 |
| 7 | 1138 |
| 8 | 1366 |
| 9 | 2276 |
| 10 | 154203 |
| 11 | 308405 |
| 12 | 616810 |
| 13 | 678491 |
| 14 | 1356981 |
| 15 | 1480343 |
| 16 | 2713962 |
| 17 | 2960686 |
| 18 | 2212558911 |
| 19 | 4425117821 |
| 20 | 8850235641 |
| 21 | 17700471281 |