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 | 3 |
| 3 | 7 |
| 4 | 20 |
| 5 | 63 |
| 6 | 233 |
| 7 | 966 |
| 8 | 4453 |
| 9 | 22367 |
| 10 | 120819 |
| 11 | 693233 |
| 12 | 4178068 |
| 13 | 26179581 |
| 14 | 169020426 |
| 15 | 1115994109 |
| 16 | 7491323062 |
| 17 | 50893512269 |
| 18 | 348746702822 |
| 19 | 2404544709055 |
| 20 | 16651752622351 |
| 21 | 115675136440751 |
| 22 | 805342277995251 |
| 23 | 5615683405472021 |
| 24 | 39202038270665250 |
| 25 | 273878789880840798 |