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 | 1 |
| 3 | 11 |
| 4 | 61 |
| 5 | 275 |
| 6 | 1141 |
| 7 | 4571 |
| 8 | 18061 |
| 9 | 71075 |
| 10 | 279781 |
| 11 | 1103531 |
| 12 | 4363261 |
| 13 | 17292275 |
| 14 | 68670421 |
| 15 | 273152891 |
| 16 | 1087959661 |
| 17 | 4337751875 |
| 18 | 17308485061 |
| 19 | 69105848651 |
| 20 | 276038071261 |
| 21 | 1102994217875 |
| 22 | 4408498475701 |
| 23 | 17623550326811 |
| 24 | 70462853802061 |
| 25 | 281757339138275 |
| 26 | 1126747061234341 |
| 27 | 4506141224763371 |