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) |
|---|---|
| 5 | 1 |
| 6 | 1 |
| 7 | 3 |
| 8 | 11 |
| 9 | 37 |
| 10 | 125 |
| 11 | 423 |
| 12 | 1429 |
| 13 | 4811 |
| 14 | 16111 |
| 15 | 53589 |
| 16 | 176905 |
| 17 | 579407 |
| 18 | 1882943 |
| 19 | 6073469 |
| 20 | 19452705 |
| 21 | 61900375 |
| 22 | 195799527 |
| 23 | 615978629 |
| 24 | 1928297807 |
| 25 | 6009527345 |
| 26 | 18653079889 |
| 27 | 57686469763 |
| 28 | 177812890843 |
| 29 | 546456642501 |
| 30 | 1674844848629 |