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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 74 |
| 5 | 15940 |
| 6 | 136888 |
| 7 | 401150 |
| 8 | 29585255 |
| 9 | 86699685 |
| 10 | 2181946705 |
| 11 | 6394201903 |
| 12 | 18738229439 |
| 13 | 54912442215 |
| 14 | 160921090214 |
| 15 | 4049856052188 |
| 16 | 34779553385863 |
| 17 | 875287288851249 |
| 18 | 7516835314214410 |
| 19 | 64553448748440886 |
| 20 | 189174091165714089 |
| 21 | 1624598582798015801 |
| 22 | 4760891422045743495 |
| 23 | 119816022336026653554 |