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 | 4 |
| 1 | 33 |
| 2 | 128 |
| 3 | 976 |
| 4 | 4032 |
| 5 | 30576 |
| 6 | 129024 |
| 7 | 976896 |
| 8 | 4188160 |
| 9 | 31728128 |
| 10 | 137478144 |
| 11 | 1042407424 |
| 12 | 4552310784 |
| 13 | 34549346304 |
| 14 | 151786618880 |
| 15 | 1152969736192 |
| 16 | 5089355366400 |
| 17 | 38688841924608 |
| 18 | 171431270809600 |
| 19 | 1304107929305088 |