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) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 147 |
| 4 | 1093 |
| 5 | 8343 |
| 6 | 64869 |
| 7 | 510891 |
| 8 | 4062277 |
| 9 | 32539647 |
| 10 | 262181601 |
| 11 | 2122581123 |
| 12 | 17252278789 |
| 13 | 140695104943 |
| 14 | 1150670390541 |
| 15 | 9433965332127 |
| 16 | 77512716483461 |
| 17 | 638080242074447 |
| 18 | 5261486780929209 |
| 19 | 43450477494413751 |
| 20 | 359308411992366513 |
| 21 | 2974886601163646379 |
| 22 | 24657831769475675253 |