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 | 4 |
| 3 | 18 |
| 4 | 93 |
| 5 | 498 |
| 6 | 2744 |
| 7 | 15349 |
| 8 | 86802 |
| 9 | 494769 |
| 10 | 2837412 |
| 11 | 16351036 |
| 12 | 94599339 |
| 13 | 549118128 |
| 14 | 3196397701 |
| 15 | 18651028188 |
| 16 | 109057492901 |
| 17 | 638863803720 |
| 18 | 3748605725140 |
| 19 | 22027421351633 |
| 20 | 129606128716906 |
| 21 | 763484925360476 |
| 22 | 4502370205339221 |
| 23 | 26577052185126059 |