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 | 4 |
| 3 | 24 |
| 4 | 201 |
| 5 | 2199 |
| 6 | 29879 |
| 7 | 486231 |
| 8 | 9228867 |
| 9 | 200272157 |
| 10 | 4892538679 |
| 11 | 132901744486 |
| 12 | 3974163191604 |
| 13 | 129735825879843 |
| 14 | 4591187990365503 |
| 15 | 175081375829138149 |
| 16 | 7157470516097359747 |
| 17 | 312267811360305253384 |
| 18 | 14481803617066951613463 |
| 19 | 711413177916751077562759 |