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 | 4 |
| 2 | 16 |
| 3 | 61 |
| 4 | 229 |
| 5 | 852 |
| 6 | 3146 |
| 7 | 11536 |
| 8 | 42032 |
| 9 | 152254 |
| 10 | 548568 |
| 11 | 1966757 |
| 12 | 7019311 |
| 13 | 24946486 |
| 14 | 88313632 |
| 15 | 311507619 |
| 16 | 1095064315 |
| 17 | 3837407016 |
| 18 | 13407618832 |
| 19 | 46715533678 |
| 20 | 162345449332 |
| 21 | 562801287366 |
| 22 | 1946559269050 |
| 23 | 6717910370343 |
| 24 | 23136984979001 |