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 | 2 |
| 3 | 45 |
| 4 | 260 |
| 5 | 1115 |
| 6 | 4230 |
| 7 | 15113 |
| 8 | 52232 |
| 9 | 176823 |
| 10 | 590090 |
| 11 | 1948133 |
| 12 | 6376716 |
| 13 | 20725523 |
| 14 | 66960782 |
| 15 | 215232705 |
| 16 | 688746512 |
| 17 | 2195381615 |
| 18 | 6973567506 |
| 19 | 22082966429 |
| 20 | 69735686420 |
| 21 | 219667415499 |
| 22 | 690383309462 |
| 23 | 2165293110905 |
| 24 | 6778308873240 |
| 25 | 21182215233575 |
| 26 | 66088511533850 |