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 | 1 |
| 3 | 5 |
| 4 | 21 |
| 5 | 89 |
| 6 | 345 |
| 7 | 1405 |
| 8 | 5501 |
| 9 | 22033 |
| 10 | 87649 |
| 11 | 350405 |
| 12 | 1398981 |
| 13 | 5596345 |
| 14 | 22373561 |
| 15 | 89492141 |
| 16 | 357930301 |
| 17 | 1431711857 |
| 18 | 5726679153 |
| 19 | 22906712645 |
| 20 | 91626189381 |
| 21 | 366504720137 |
| 22 | 1466016390873 |
| 23 | 5864065352173 |
| 24 | 23456251396589 |
| 25 | 93825005578001 |
| 26 | 375299982311441 |
| 27 | 1501199928316661 |