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 | 21 |
| 2 | 23 |
| 3 | 67 |
| 4 | 259 |
| 5 | 1074 |
| 6 | 3788 |
| 7 | 13767 |
| 8 | 53839 |
| 9 | 201274 |
| 10 | 741275 |
| 11 | 2806825 |
| 12 | 10575217 |
| 13 | 39423977 |
| 14 | 147990910 |
| 15 | 556562343 |
| 16 | 2084799226 |
| 17 | 7816395336 |
| 18 | 29347218029 |
| 19 | 110071768648 |
| 20 | 412764006652 |
| 21 | 1548711236567 |
| 22 | 5809916135249 |
| 23 | 21791597835454 |