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 | 18 |
| 2 | 126 |
| 3 | 560 |
| 4 | 1890 |
| 5 | 5292 |
| 6 | 12936 |
| 7 | 28512 |
| 8 | 57915 |
| 9 | 110110 |
| 10 | 198198 |
| 11 | 340704 |
| 12 | 563108 |
| 13 | 899640 |
| 14 | 1395360 |
| 15 | 2108544 |
| 16 | 3113397 |
| 17 | 4503114 |
| 18 | 6393310 |
| 19 | 8925840 |
| 20 | 12273030 |
| 21 | 16642340 |
| 22 | 22281480 |
| 23 | 29484000 |
| 24 | 38595375 |
| 25 | 50019606 |
| 26 | 64226358 |
| 27 | 81758656 |
| 28 | 103241160 |
| 29 | 129389040 |
| 30 | 161017472 |
| 31 | 199051776 |