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 | 0 |
| 1 | 1 |
| 2 | 15 |
| 3 | 99 |
| 4 | 435 |
| 5 | 1485 |
| 6 | 4257 |
| 7 | 10725 |
| 8 | 24453 |
| 9 | 51480 |
| 10 | 101530 |
| 11 | 189618 |
| 12 | 338130 |
| 13 | 579462 |
| 14 | 959310 |
| 15 | 1540710 |
| 16 | 2408934 |
| 17 | 3677355 |
| 18 | 5494401 |
| 19 | 8051725 |
| 20 | 11593725 |
| 21 | 16428555 |
| 22 | 22940775 |
| 23 | 31605795 |
| 24 | 43006275 |
| 25 | 57850650 |
| 26 | 76993956 |
| 27 | 101461140 |
| 28 | 132473044 |
| 29 | 171475260 |
| 30 | 220170060 |
| 31 | 280551612 |