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) |
|---|---|
| 2 | 4 |
| 3 | 22 |
| 4 | 108 |
| 5 | 490 |
| 6 | 2164 |
| 7 | 9474 |
| 8 | 41374 |
| 9 | 180614 |
| 10 | 788676 |
| 11 | 3445462 |
| 12 | 15059202 |
| 13 | 65847946 |
| 14 | 288033326 |
| 15 | 1260313930 |
| 16 | 5516051890 |
| 17 | 24147542122 |
| 18 | 105729680608 |
| 19 | 463006798298 |
| 20 | 2027839420598 |
| 21 | 8882324416302 |
| 22 | 38909820194506 |
| 23 | 170461077652718 |
| 24 | 746826223566214 |
| 25 | 3272185833672630 |