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 | 3 |
| 3 | 19 |
| 4 | 207 |
| 5 | 3691 |
| 6 | 103263 |
| 7 | 4415419 |
| 8 | 283796607 |
| 9 | 27094905451 |
| 10 | 3813398797023 |
| 11 | 786844659227419 |
| 12 | 237151202183603007 |
| 13 | 104128385332221915211 |
| 14 | 66478899089080159079583 |
| 15 | 61624041121329496987905019 |