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 | 21 |
| 4 | 76 |
| 5 | 249 |
| 6 | 814 |
| 7 | 2521 |
| 8 | 7824 |
| 9 | 23473 |
| 10 | 70590 |
| 11 | 207345 |
| 12 | 610356 |
| 13 | 1765959 |
| 14 | 511006 |
| 15 | 14643993 |
| 16 | 41958852 |
| 17 | 118976633 |
| 18 | 337823486 |
| 19 | 951157365 |
| 20 | 2681163492 |
| 21 | 7505218171 |
| 22 | 21030311474 |