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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 35 |
| 6 | 129 |
| 7 | 494 |
| 8 | 1935 |
| 9 | 7670 |
| 10 | 30582 |
| 11 | 122280 |
| 12 | 489552 |
| 13 | 1960956 |
| 14 | 7855994 |
| 15 | 31471731 |
| 16 | 126063782 |
| 17 | 504888839 |
| 18 | 2021777865 |
| 19 | 8094784697 |
| 20 | 32405289263 |
| 21 | 129709206465 |
| 22 | 519129580361 |
| 23 | 2077477804103 |
| 24 | 8313000733125 |
| 25 | 33261722967167 |
| 26 | 133076495664483 |
| 27 | 532391828669675 |
| 28 | 2129796460981743 |
| 29 | 8519701993370619 |
| 30 | 34079469569317323 |