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 | 13 |
| 2 | 86 |
| 3 | 603 |
| 4 | 4620 |
| 5 | 37299 |
| 6 | 1533327 |
| 7 | 22568442 |
| 8 | 23574105 |
| 9 | 210014510 |
| 10 | 1893613727 |
| 11 | 17241353173 |
| 12 | 493582559244 |
| 13 | 13474975578701 |
| 14 | 71056054875827 |
| 15 | 1180956491651370 |
| 16 | 10728352138939963 |
| 17 | 103710009988272649 |
| 18 | 960912626678471376 |
| 19 | 1005142876338508545 |
| 20 | 50686811139876408310 |
| 21 | 288867303325879381560 |