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 | 5 |
| 3 | 15 |
| 4 | 45 |
| 5 | 120 |
| 6 | 326 |
| 7 | 835 |
| 8 | 2145 |
| 9 | 5345 |
| 10 | 13220 |
| 11 | 32068 |
| 12 | 76965 |
| 13 | 181975 |
| 14 | 425490 |
| 15 | 982615 |
| 16 | 2245444 |
| 17 | 5077090 |
| 18 | 11371250 |
| 19 | 25235790 |
| 20 | 55536870 |
| 21 | 121250185 |
| 22 | 262769080 |
| 23 | 565502405 |
| 24 | 1209096875 |
| 25 | 2569270050 |
| 26 | 5427963902 |
| 27 | 11404408525 |
| 28 | 23836421895 |
| 29 | 49573316740 |
| 30 | 102610460240 |