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 | 28 |
| 3 | 109 |
| 4 | 380 |
| 5 | 2450 |
| 6 | 12075 |
| 7 | 55471 |
| 8 | 286079 |
| 9 | 1429824 |
| 10 | 6989477 |
| 11 | 34856362 |
| 12 | 173451524 |
| 13 | 858586095 |
| 14 | 4263159553 |
| 15 | 21172762001 |
| 16 | 105041615196 |
| 17 | 521348098233 |
| 18 | 2587930504660 |
| 19 | 12843811121650 |
| 20 | 63746482751185 |
| 21 | 316398514788731 |