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 | 3 |
| 2 | 30 |
| 3 | 144 |
| 4 | 588 |
| 5 | 2160 |
| 6 | 7440 |
| 7 | 24576 |
| 8 | 78912 |
| 9 | 248448 |
| 10 | 771456 |
| 11 | 2371968 |
| 12 | 7241856 |
| 13 | 21998976 |
| 14 | 66586752 |
| 15 | 201025920 |
| 16 | 605781120 |
| 17 | 1823094144 |
| 18 | 5481472128 |
| 19 | 16470172032 |
| 20 | 49464779904 |
| 21 | 148508372352 |
| 22 | 445764192384 |
| 23 | 1337792747904 |