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 | 6 |
| 2 | 21 |
| 3 | 76 |
| 4 | 336 |
| 5 | 1560 |
| 6 | 7826 |
| 7 | 39996 |
| 8 | 210126 |
| 9 | 1119796 |
| 10 | 6047412 |
| 11 | 32981556 |
| 12 | 181402676 |
| 13 | 1004668776 |
| 14 | 5597460306 |
| 15 | 31345666736 |
| 16 | 176319474366 |
| 17 | 995685849696 |
| 18 | 5642220380006 |
| 19 | 32071565263716 |
| 20 | 182807925027504 |
| 21 | 1044616697187576 |
| 22 | 5982804736593846 |