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 | 9 |
| 2 | 73 |
| 3 | 201 |
| 4 | 457 |
| 5 | 969 |
| 6 | 9161 |
| 7 | 140233 |
| 8 | 402377 |
| 9 | 2499529 |
| 10 | 6693833 |
| 11 | 15082441 |
| 12 | 31859657 |
| 13 | 65414089 |
| 14 | 132522953 |
| 15 | 1206264777 |
| 16 | 3353748425 |
| 17 | 11943683017 |
| 18 | 29123552201 |
| 19 | 63483290569 |
| 20 | 132202767305 |
| 21 | 269641720777 |
| 22 | 819397534665 |