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 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 38 |
| 5 | 166 |
| 6 | 891 |
| 7 | 4326 |
| 8 | 21985 |
| 9 | 109567 |
| 10 | 551027 |
| 11 | 2759757 |
| 12 | 13846871 |
| 13 | 69418237 |
| 14 | 348143326 |
| 15 | 1745704167 |
| 16 | 8754189034 |
| 17 | 43898170484 |
| 18 | 220132165897 |
| 19 | 1103869189670 |
| 20 | 5535451646119 |
| 21 | 27757983230949 |
| 22 | 139194805502163 |
| 23 | 698004183274703 |