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 | 4 |
| 2 | 29 |
| 3 | 140 |
| 4 | 741 |
| 5 | 3853 |
| 6 | 19956 |
| 7 | 104096 |
| 8 | 541775 |
| 9 | 2819027 |
| 10 | 14671776 |
| 11 | 76356631 |
| 12 | 397392690 |
| 13 | 2068192977 |
| 14 | 10763659993 |
| 15 | 56018290276 |
| 16 | 291541126302 |
| 17 | 1517293977155 |
| 18 | 7896590852333 |
| 19 | 41096944195828 |
| 20 | 213884557644749 |
| 21 | 1113138825391146 |