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 | 7 |
| 3 | 15 |
| 4 | 35 |
| 5 | 83 |
| 6 | 199 |
| 7 | 479 |
| 8 | 1155 |
| 9 | 2787 |
| 10 | 6727 |
| 11 | 16239 |
| 12 | 39203 |
| 13 | 94643 |
| 14 | 228487 |
| 15 | 551615 |
| 16 | 1331715 |
| 17 | 3215043 |
| 18 | 7761799 |
| 19 | 18738639 |
| 20 | 45239075 |
| 21 | 109216787 |
| 22 | 263672647 |
| 23 | 636562079 |
| 24 | 1536796803 |
| 25 | 3710155683 |
| 26 | 8957108167 |
| 27 | 21624372015 |
| 28 | 52205852195 |