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 | 17 |
| 4 | 145 |
| 5 | 1661 |
| 6 | 23931 |
| 7 | 415773 |
| 8 | 8460257 |
| 9 | 197360985 |
| 10 | 5192853011 |
| 11 | 152137882601 |
| 12 | 4911873672113 |
| 13 | 173268075672277 |
| 14 | 6630323916472075 |
| 15 | 273555262963272501 |
| 16 | 12105084133976359361 |
| 17 | 571897644855277242673 |
| 18 | 28731255563712689630627 |
| 19 | 1529450942687399074134465 |