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 | 0 |
| 2 | 30 |
| 3 | 126 |
| 4 | 201 |
| 5 | 570 |
| 6 | 2550 |
| 7 | 3369 |
| 8 | 3873 |
| 9 | 14565 |
| 10 | 41958 |
| 11 | 54441 |
| 12 | 62625 |
| 13 | 64641 |
| 14 | 171990 |
| 15 | 234405 |
| 16 | 254865 |
| 17 | 873129 |
| 18 | 954261 |
| 19 | 1004193 |
| 20 | 1036929 |
| 21 | 1044993 |
| 22 | 2788950 |
| 23 | 3755685 |
| 24 | 4083345 |
| 25 | 4165185 |
| 26 | 11140950 |
| 27 | 13978281 |
| 28 | 15285909 |
| 29 | 16075425 |
| 30 | 16399953 |
| 31 | 16599681 |