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 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 51 |
| 6 | 196 |
| 7 | 827 |
| 8 | 3795 |
| 9 | 18755 |
| 10 | 99146 |
| 11 | 556711 |
| 12 | 3305017 |
| 13 | 20655285 |
| 14 | 135399720 |
| 15 | 927973061 |
| 16 | 6631556521 |
| 17 | 49294051497 |
| 18 | 380306658250 |
| 19 | 3039453750685 |
| 20 | 25120541332271 |
| 21 | 214363100120051 |
| 22 | 1885987611214092 |
| 23 | 17085579637664715 |
| 24 | 159185637725413675 |