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 | 80 |
| 3 | 1395 |
| 4 | 12560 |
| 5 | 96575 |
| 6 | 698940 |
| 7 | 4897655 |
| 8 | 33590720 |
| 9 | 226746135 |
| 10 | 1511651900 |
| 11 | 9976916015 |
| 12 | 65303466480 |
| 13 | 424472551295 |
| 14 | 2742745738460 |
| 15 | 17631936915975 |
| 16 | 112844396291840 |
| 17 | 719383026394055 |
| 18 | 4570198050070620 |
| 19 | 28944587650489535 |
| 20 | 182807922003138800 |
| 21 | 1151689908619826415 |