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 | 3 |
| 3 | 9 |
| 4 | 23 |
| 5 | 57 |
| 6 | 139 |
| 7 | 337 |
| 8 | 815 |
| 9 | 1969 |
| 10 | 4755 |
| 11 | 11481 |
| 12 | 27719 |
| 13 | 66921 |
| 14 | 161563 |
| 15 | 390049 |
| 16 | 941663 |
| 17 | 2273377 |
| 18 | 5488419 |
| 19 | 13250217 |
| 20 | 31988855 |
| 21 | 77227929 |
| 22 | 186444715 |
| 23 | 450117361 |
| 24 | 1086679439 |
| 25 | 2623476241 |
| 26 | 6333631923 |
| 27 | 15290740089 |
| 28 | 36915112103 |
| 29 | 89120964297 |
| 30 | 215157040699 |