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 | 26 |
| 4 | 150 |
| 5 | 1114 |
| 6 | 10614 |
| 7 | 131002 |
| 8 | 2128278 |
| 9 | 46294426 |
| 10 | 1368718518 |
| 11 | 55647242106 |
| 12 | 3137452915158 |
| 13 | 246751601425242 |
| 14 | 27181289502625014 |
| 15 | 4205716133932054842 |
| 16 | 915890632125187606038 |
| 17 | 281117681559174501597466 |
| 18 | 121733516122198763782243638 |