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 | 2 |
| 2 | 9 |
| 3 | 36 |
| 4 | 135 |
| 5 | 498 |
| 6 | 1841 |
| 7 | 6856 |
| 8 | 25731 |
| 9 | 97230 |
| 10 | 369501 |
| 11 | 1410852 |
| 12 | 5408299 |
| 13 | 20801186 |
| 14 | 80233185 |
| 15 | 310235024 |
| 16 | 1202160763 |
| 17 | 4667212422 |
| 18 | 18150270581 |
| 19 | 70690527580 |
| 20 | 275693057619 |
| 21 | 1076515748858 |
| 22 | 4208197927417 |
| 23 | 16466861455176 |
| 24 | 64495207366175 |
| 25 | 252821212875478 |