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 | 6 |
| 4 | 20 |
| 5 | 60 |
| 6 | 291 |
| 7 | 1310 |
| 8 | 6975 |
| 9 | 37746 |
| 10 | 215602 |
| 11 | 1262874 |
| 12 | 7611156 |
| 13 | 46814132 |
| 14 | 293447817 |
| 15 | 1868710728 |
| 16 | 12068905911 |
| 17 | 78913940784 |
| 18 | 521709872895 |
| 19 | 3483289035186 |
| 20 | 23464708686960 |
| 21 | 159346213738020 |
| 22 | 1090073011199451 |
| 23 | 7507285094455566 |
| 24 | 52021636161126702 |