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 | 150 |
| 3 | 3000 |
| 4 | 37500 |
| 5 | 375000 |
| 6 | 3281250 |
| 7 | 26250000 |
| 8 | 196875000 |
| 9 | 1406250000 |
| 10 | 9667968750 |
| 11 | 64453125000 |
| 12 | 418945312500 |
| 13 | 2666015625000 |
| 14 | 16662597656250 |
| 15 | 102539062500000 |
| 16 | 622558593750000 |
| 17 | 3735351562500000 |
| 18 | 22178649902343750 |
| 19 | 130462646484375000 |
| 20 | 761032104492187500 |