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 | 7 |
| 3 | 40 |
| 4 | 281 |
| 5 | 2006 |
| 6 | 17677 |
| 7 | 159020 |
| 8 | 1678721 |
| 9 | 18555850 |
| 10 | 230978981 |
| 11 | 2979853592 |
| 12 | 43323807265 |
| 13 | 644160764846 |
| 14 | 10543905398405 |
| 15 | 178896116995276 |
| 16 | 3284281839169217 |
| 17 | 61879477543508690 |
| 18 | 1264313089711322821 |
| 19 | 26333205612282941600 |
| 20 | 588074615109602665601 |