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 | 4 |
| 3 | 15 |
| 4 | 71 |
| 5 | 269 |
| 6 | 1274 |
| 7 | 4827 |
| 8 | 22861 |
| 9 | 86617 |
| 10 | 410224 |
| 11 | 1554279 |
| 12 | 7361171 |
| 13 | 27890405 |
| 14 | 132090854 |
| 15 | 500473011 |
| 16 | 2370274201 |
| 17 | 8980623793 |
| 18 | 42532844764 |
| 19 | 161150755263 |
| 20 | 763220931551 |
| 21 | 2891732970941 |
| 22 | 13695443923154 |
| 23 | 51890042721675 |