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 | 5 |
| 1 | 21 |
| 2 | 101 |
| 3 | 501 |
| 4 | 2501 |
| 5 | 12501 |
| 6 | 62501 |
| 7 | 312501 |
| 8 | 1562501 |
| 9 | 7812501 |
| 10 | 39062501 |
| 11 | 195312501 |
| 12 | 976562501 |
| 13 | 4882812501 |
| 14 | 24414062501 |
| 15 | 122070312501 |
| 16 | 610351562501 |
| 17 | 3051757812501 |
| 18 | 15258789062501 |
| 19 | 76293945312501 |
| 20 | 381469726562501 |
| 21 | 1907348632812501 |
| 22 | 9536743164062501 |
| 23 | 47683715820312501 |