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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 8 |
| 6 | 32 |
| 7 | 168 |
| 8 | 616 |
| 9 | 2380 |
| 10 | 8472 |
| 11 | 30760 |
| 12 | 109644 |
| 13 | 394816 |
| 14 | 1420784 |
| 15 | 5149948 |
| 16 | 18736744 |
| 17 | 68553728 |
| 18 | 251902032 |
| 19 | 929814984 |
| 20 | 3445433608 |
| 21 | 12814382620 |
| 22 | 47817551136 |
| 23 | 178982546512 |
| 24 | 671813695340 |
| 25 | 2528191984504 |
| 26 | 9536849826816 |