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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 10 |
| 4 | 77 |
| 5 | 546 |
| 6 | 3740 |
| 7 | 25194 |
| 8 | 168245 |
| 9 | 1118260 |
| 10 | 7413705 |
| 11 | 49085400 |
| 12 | 324794316 |
| 13 | 2148789800 |
| 14 | 14217578856 |
| 15 | 94096891658 |
| 16 | 622997471685 |
| 17 | 4126520887720 |
| 18 | 27345271410275 |
| 19 | 181295437422330 |
| 20 | 1202538435463365 |
| 21 | 7980245606038650 |