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 | 2 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 9 |
| 6 | 7 |
| 7 | 21 |
| 8 | 63 |
| 9 | 157 |
| 10 | 471 |
| 11 | 5 |
| 12 | 15 |
| 13 | 45 |
| 14 | 135 |
| 15 | 405 |
| 16 | 1215 |
| 17 | 3645 |
| 18 | 10935 |
| 19 | 32805 |
| 20 | 98415 |
| 21 | 295245 |
| 22 | 885735 |
| 23 | 2657205 |
| 24 | 4409119 |
| 25 | 2741597 |
| 26 | 8224791 |
| 27 | 16285765 |
| 28 | 15302863 |
| 29 | 45908589 |
| 30 | 137725767 |
| 31 | 77632981 |
| 32 | 232898943 |
| 33 | 161825917 |
| 34 | 485477751 |
| 35 | 1456433253 |
| 36 | 3027122479 |
| 37 | 1565174669 |