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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 38 |
| 5 | 250 |
| 6 | 2367 |
| 7 | 29197 |
| 8 | 441212 |
| 9 | 7874244 |
| 10 | 161950445 |
| 11 | 3770473399 |
| 12 | 98009367282 |
| 13 | 2813394489022 |
| 14 | 88387455559067 |
| 15 | 3016497635377545 |
| 16 | 111127442649962168 |
| 17 | 4395316276005329608 |
| 18 | 185766120783135345177 |
| 19 | 8355290720655784462507 |
| 20 | 398470047793625748742670 |
| 21 | 20084626943220497590901346 |