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 | 2 |
| 2 | 6 |
| 3 | 10 |
| 4 | 30 |
| 5 | 70 |
| 6 | 210 |
| 7 | 770 |
| 8 | 2310 |
| 9 | 10010 |
| 10 | 30030 |
| 11 | 34034 |
| 12 | 170170 |
| 13 | 510510 |
| 14 | 646646 |
| 15 | 3233230 |
| 16 | 9699690 |
| 17 | 14872858 |
| 18 | 74364290 |
| 19 | 223092870 |
| 20 | 431312882 |
| 21 | 2156564410 |
| 22 | 6469693230 |
| 23 | 13370699342 |
| 24 | 66853496710 |
| 25 | 200560490130 |
| 26 | 494715875654 |
| 27 | 2473579378270 |
| 28 | 7420738134810 |
| 29 | 20283350901814 |