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 | 6 |
| 3 | 25 |
| 4 | 104 |
| 5 | 414 |
| 6 | 1636 |
| 7 | 6375 |
| 8 | 24591 |
| 9 | 94257 |
| 10 | 360002 |
| 11 | 1371535 |
| 12 | 5216252 |
| 13 | 19819846 |
| 14 | 75277670 |
| 15 | 285893124 |
| 16 | 1085984406 |
| 17 | 4126777398 |
| 18 | 15690144942 |
| 19 | 59691687518 |
| 20 | 227248928264 |
| 21 | 865788366806 |
| 22 | 3301087870766 |
| 23 | 12596381911969 |
| 24 | 48104063936789 |