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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 36 |
| 6 | 118 |
| 7 | 456 |
| 8 | 1816 |
| 9 | 7888 |
| 10 | 37354 |
| 11 | 184064 |
| 12 | 974372 |
| 13 | 5444544 |
| 14 | 31769182 |
| 15 | 195982208 |
| 16 | 1259350576 |
| 17 | 8441139456 |
| 18 | 59073098706 |
| 19 | 428299217920 |
| 20 | 3226127944764 |
| 21 | 25165446157312 |
| 22 | 202778723085382 |
| 23 | 1689266143553536 |