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 | 3 |
| 2 | 21 |
| 3 | 219 |
| 4 | 3045 |
| 5 | 52923 |
| 6 | 1103781 |
| 7 | 26857659 |
| 8 | 746870565 |
| 9 | 23365498683 |
| 10 | 812198635941 |
| 11 | 31055758599099 |
| 12 | 1295419975298085 |
| 13 | 58538439796931643 |
| 14 | 2848763394161128101 |
| 15 | 148537065755389540539 |
| 16 | 8261178848690959117605 |
| 17 | 488177936257344615487803 |
| 18 | 30544839926043868901604261 |