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 | 6 |
| 3 | 21 |
| 4 | 71 |
| 5 | 251 |
| 6 | 882 |
| 7 | 3088 |
| 8 | 10829 |
| 9 | 37975 |
| 10 | 133146 |
| 11 | 466852 |
| 12 | 1636944 |
| 13 | 5739647 |
| 14 | 20125051 |
| 15 | 70564951 |
| 16 | 247423522 |
| 17 | 867546829 |
| 18 | 3041899638 |
| 19 | 10665883415 |
| 20 | 37398034921 |
| 21 | 131129599227 |
| 22 | 459782762029 |
| 23 | 1612146986543 |
| 24 | 5652708454881 |
| 25 | 19820223058176 |
| 26 | 69496108849357 |