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 | 43 |
| 3 | 190 |
| 4 | 1562 |
| 5 | 6364 |
| 6 | 56785 |
| 7 | 645030 |
| 8 | 3115659 |
| 9 | 14645261 |
| 10 | 14645261 |
| 11 | 297120510 |
| 12 | 8206427482 |
| 13 | 22047714683 |
| 14 | 118936725090 |
| 15 | 118936725090 |
| 16 | 23856744274805 |
| 17 | 123555535983608 |
| 18 | 588816563958022 |
| 19 | 5474057357689369 |
| 20 | 51069638099181941 |
| 21 | 51069638099181941 |