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 | 30 |
| 3 | 70 |
| 4 | 210 |
| 5 | 462 |
| 6 | 6006 |
| 7 | 4290 |
| 8 | 72930 |
| 9 | 461890 |
| 10 | 1939938 |
| 11 | 4056234 |
| 12 | 6760390 |
| 13 | 1560090 |
| 14 | 6463230 |
| 15 | 200360130 |
| 16 | 2203961430 |
| 17 | 907513530 |
| 18 | 33578000610 |
| 19 | 22974421470 |
| 20 | 941951280270 |
| 21 | 5786272150230 |
| 22 | 526024740930 |
| 23 | 1074920122770 |
| 24 | 7524440859390 |
| 25 | 25583098921926 |
| 26 | 104300326374006 |
| 27 | 1912172650190110 |