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 | 37 |
| 5 | 92 |
| 6 | 225 |
| 7 | 555 |
| 8 | 1369 |
| 9 | 3375 |
| 10 | 8324 |
| 11 | 20528 |
| 12 | 50625 |
| 13 | 124852 |
| 14 | 307912 |
| 15 | 759375 |
| 16 | 1872780 |
| 17 | 4618673 |
| 18 | 11390625 |
| 19 | 28091697 |
| 20 | 69280083 |
| 21 | 170859375 |
| 22 | 421375454 |
| 23 | 1039201232 |
| 24 | 2562890625 |
| 25 | 6320631805 |
| 26 | 15588018474 |
| 27 | 38443359375 |
| 28 | 94809477069 |
| 29 | 233820277108 |