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 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 10 |
| 6 | 0 |
| 7 | 14 |
| 8 | 112 |
| 9 | 282 |
| 10 | 600 |
| 11 | 2618 |
| 12 | 9400 |
| 13 | 27378 |
| 14 | 93828 |
| 15 | 332070 |
| 16 | 1127840 |
| 17 | 3818438 |
| 18 | 13369560 |
| 19 | 46776898 |
| 20 | 163073440 |
| 21 | 572984748 |
| 22 | 2026468708 |
| 23 | 7176533646 |