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 | 1 |
| 2 | 21 |
| 3 | 331 |
| 4 | 6181 |
| 5 | 116601 |
| 6 | 2248575 |
| 7 | 43874139 |
| 8 | 864287973 |
| 9 | 17148949027 |
| 10 | 342237634221 |
| 11 | 6862175029689 |
| 12 | 138132246844879 |
| 13 | 2789732439723061 |
| 14 | 56501091296763855 |
| 15 | 1147129435985083731 |
| 16 | 23339695295337149925 |
| 17 | 475767618472211229549 |
| 18 | 9714486212587875804351 |