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 | 1 |
| 3 | 4 |
| 4 | 17 |
| 5 | 74 |
| 6 | 356 |
| 7 | 1808 |
| 8 | 9923 |
| 9 | 57442 |
| 10 | 354407 |
| 11 | 2296028 |
| 12 | 15704028 |
| 13 | 112266048 |
| 14 | 841442105 |
| 15 | 6564854864 |
| 16 | 53413489773 |
| 17 | 450789496454 |
| 18 | 3950844987040 |
| 19 | 35809477617544 |
| 20 | 335901221506491 |
| 21 | 3250110998386534 |
| 22 | 32453151223493139 |
| 23 | 333520967584364248 |
| 24 | 3528754456836294712 |