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 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 94 |
| 5 | 454 |
| 6 | 2430 |
| 7 | 14214 |
| 8 | 89918 |
| 9 | 610182 |
| 10 | 4412798 |
| 11 | 33827974 |
| 12 | 273646526 |
| 13 | 2326980998 |
| 14 | 20732504062 |
| 15 | 192982729350 |
| 16 | 1871953992254 |
| 17 | 18880288847750 |
| 18 | 197601208474238 |
| 19 | 2142184050841734 |
| 20 | 24016181943732414 |
| 21 | 278028611833689478 |
| 22 | 3319156078802044158 |
| 23 | 40811417293301014150 |