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 | 15 |
| 3 | 29 |
| 4 | 239 |
| 5 | 645 |
| 6 | 3991 |
| 7 | 13021 |
| 8 | 68895 |
| 9 | 251189 |
| 10 | 1215719 |
| 11 | 4732365 |
| 12 | 21752431 |
| 13 | 88005541 |
| 14 | 392539575 |
| 15 | 1624617149 |
| 16 | 7120171199 |
| 17 | 29864811285 |
| 18 | 129547208071 |
| 19 | 547654566061 |
| 20 | 2361315479055 |
| 21 | 10028479403909 |
| 22 | 43086896110679 |
| 23 | 183485607765405 |
| 24 | 786702153314911 |
| 25 | 3355500662030581 |