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 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 37 |
| 6 | 177 |
| 7 | 959 |
| 8 | 6097 |
| 9 | 41641 |
| 10 | 325249 |
| 11 | 2693691 |
| 12 | 24807321 |
| 13 | 241586893 |
| 14 | 2558036145 |
| 15 | 28607094455 |
| 16 | 342232522657 |
| 17 | 4315903789009 |
| 18 | 57569080467073 |
| 19 | 807258131578995 |
| 20 | 11879658510739497 |
| 21 | 183184249105857781 |
| 22 | 2948163649552594737 |
| 23 | 49548882107764546223 |