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) |
|---|---|
| 4 | 2 |
| 5 | 16 |
| 6 | 98 |
| 7 | 500 |
| 8 | 2308 |
| 9 | 9920 |
| 10 | 40522 |
| 11 | 159212 |
| 12 | 606790 |
| 13 | 2256544 |
| 14 | 8224202 |
| 15 | 29473012 |
| 16 | 104124044 |
| 17 | 363374560 |
| 18 | 1254711038 |
| 19 | 4292365876 |
| 20 | 14564351510 |
| 21 | 49059814576 |
| 22 | 164186524940 |
| 23 | 546276316120 |
| 24 | 1807990549352 |
| 25 | 5955265349696 |
| 26 | 19530431537488 |
| 27 | 63795464433440 |
| 28 | 207623760855106 |
| 29 | 673440401953856 |