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) |
|---|---|
| 17 | 1 |
| 18 | 18 |
| 19 | 171 |
| 20 | 1140 |
| 21 | 5985 |
| 22 | 26334 |
| 23 | 100947 |
| 24 | 346104 |
| 25 | 1081575 |
| 26 | 3124550 |
| 27 | 8436285 |
| 28 | 21474180 |
| 29 | 51895935 |
| 30 | 119759850 |
| 31 | 265182525 |
| 32 | 565722720 |
| 33 | 1166803110 |
| 34 | 2333606220 |
| 35 | 4537567650 |
| 36 | 8597496600 |
| 37 | 15905368710 |
| 38 | 28781143380 |
| 39 | 51021117810 |
| 40 | 88732378800 |
| 41 | 151584480450 |
| 42 | 254661927156 |