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 | 5 |
| 2 | 10 |
| 3 | 40 |
| 4 | 110 |
| 5 | 430 |
| 6 | 1420 |
| 7 | 5720 |
| 8 | 21340 |
| 9 | 89980 |
| 10 | 367400 |
| 11 | 1627120 |
| 12 | 7138120 |
| 13 | 33172040 |
| 14 | 154520080 |
| 15 | 751616800 |
| 16 | 3687498320 |
| 17 | 18719834320 |
| 18 | 96157299040 |
| 19 | 507993654080 |
| 20 | 2719611532000 |
| 21 | 14911459229920 |
| 22 | 82901747529920 |
| 23 | 470599687507840 |
| 24 | 2708946870815680 |