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 | 0 |
| 1 | 10 |
| 2 | 530 |
| 3 | 19710 |
| 4 | 262180 |
| 5 | 1953170 |
| 6 | 10077750 |
| 7 | 40353670 |
| 8 | 134217800 |
| 9 | 387420570 |
| 10 | 1000000090 |
| 11 | 2357947790 |
| 12 | 5159780460 |
| 13 | 10604499490 |
| 14 | 20661046910 |
| 15 | 38443359510 |
| 16 | 68719476880 |
| 17 | 118587876650 |
| 18 | 198359290530 |
| 19 | 322687697950 |
| 20 | 512000000180 |