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 | 6 |
| 2 | 23 |
| 3 | 80 |
| 4 | 285 |
| 5 | 990 |
| 6 | 3367 |
| 7 | 11256 |
| 8 | 37097 |
| 9 | 120862 |
| 10 | 390123 |
| 11 | 1249728 |
| 12 | 3978365 |
| 13 | 12598350 |
| 14 | 39718403 |
| 15 | 124743104 |
| 16 | 390491505 |
| 17 | 1218875302 |
| 18 | 3794984883 |
| 19 | 11789335464 |
| 20 | 36551285573 |
| 21 | 113120066678 |
| 22 | 349523991123 |
| 23 | 1078402178776 |