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 | 3 |
| 1 | 12 |
| 2 | 42 |
| 3 | 312 |
| 4 | 942 |
| 5 | 6264 |
| 6 | 25284 |
| 7 | 162000 |
| 8 | 620460 |
| 9 | 4961280 |
| 10 | 16161768 |
| 11 | 103442688 |
| 12 | 367381884 |
| 13 | 2441936064 |
| 14 | 9859525284 |
| 15 | 76963663296 |
| 16 | 228970112844 |
| 17 | 1526377433328 |
| 18 | 6339280635408 |
| 19 | 38199227335200 |
| 20 | 144103649734968 |
| 21 | 1285221510144000 |
| 22 | 3894650946433800 |
| 23 | 24349131482713344 |