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 | 1 |
| 5 | 11 |
| 6 | 80 |
| 7 | 491 |
| 8 | 2777 |
| 9 | 15120 |
| 10 | 81371 |
| 11 | 440947 |
| 12 | 2441334 |
| 13 | 13976885 |
| 14 | 83547881 |
| 15 | 525082654 |
| 16 | 3483272777 |
| 17 | 24413200487 |
| 18 | 180517606216 |
| 19 | 1404147099951 |
| 20 | 11449330342717 |
| 21 | 97521479081952 |
| 22 | 864955731435983 |
| 23 | 7966538662094103 |