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 | 5 |
| 2 | 25 |
| 3 | 120 |
| 4 | 572 |
| 5 | 2692 |
| 6 | 12570 |
| 7 | 58280 |
| 8 | 268704 |
| 9 | 1233046 |
| 10 | 5636046 |
| 11 | 25675580 |
| 12 | 116635916 |
| 13 | 528551090 |
| 14 | 2390183046 |
| 15 | 10789164304 |
| 16 | 48625122028 |
| 17 | 218845692934 |
| 18 | 983773248134 |
| 19 | 4417701453060 |
| 20 | 19819733378212 |
| 21 | 88847987191058 |
| 22 | 398004177820814 |