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 | 20 |
| 3 | 102 |
| 4 | 254 |
| 5 | 1017 |
| 6 | 5263 |
| 7 | 20771 |
| 8 | 76340 |
| 9 | 320326 |
| 10 | 1353690 |
| 11 | 5389975 |
| 12 | 21589173 |
| 13 | 88747475 |
| 14 | 362176212 |
| 15 | 1462891858 |
| 16 | 5938102840 |
| 17 | 24195113809 |
| 18 | 98303450371 |
| 19 | 398918472477 |
| 20 | 1621218682358 |
| 21 | 6590614515512 |
| 22 | 26773290621678 |
| 23 | 108760910018039 |