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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 8 |
| 7 | 16 |
| 8 | 32 |
| 9 | 96 |
| 10 | 288 |
| 11 | 864 |
| 12 | 2592 |
| 13 | 7776 |
| 14 | 23328 |
| 15 | 69984 |
| 16 | 279936 |
| 17 | 1119744 |
| 18 | 4478976 |
| 19 | 17915904 |
| 20 | 71663616 |
| 21 | 286654464 |
| 22 | 1146617856 |
| 23 | 4586471424 |
| 24 | 18345885696 |
| 25 | 91729428480 |
| 26 | 458647142400 |
| 27 | 2293235712000 |
| 28 | 11466178560000 |
| 29 | 57330892800000 |
| 30 | 286654464000000 |