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 | 1 |
| 2 | 4 |
| 3 | 15 |
| 4 | 52 |
| 5 | 197 |
| 6 | 896 |
| 7 | 4987 |
| 8 | 33216 |
| 9 | 257161 |
| 10 | 2262124 |
| 11 | 22241671 |
| 12 | 241476060 |
| 13 | 2867551117 |
| 14 | 36960108680 |
| 15 | 513753523571 |
| 16 | 7659705147976 |
| 17 | 121918431264273 |
| 18 | 2063255678027668 |
| 19 | 36991535865656959 |
| 20 | 700377953116334788 |
| 21 | 13963866589144933461 |
| 22 | 292421219327021540176 |
| 23 | 6417047546280200867819 |